There’s Something in the Water

In the fast paced world of weather, Hurricane Irma is old news. There’s already a Wikipedia page on it. But, people that were in Irma’s path are still cleaning up (at least at the time I’m writing this). In case you’ve already forgotten, or were living in a Faraday cage underground, here’s a quick recap. Among the factoids: Irma was the strongest hurricane ever recorded in the Atlantic basin and it was a Category 5 (the highest the scale goes) for the longest period of time of any Atlantic hurricane. The island of Barbuda took a direct hit from Irma and is now desolate and decimated. Jacksonville, which did not take a direct hit, received record flooding due to winds blowing the St. Johns River inland, while heavy rains inland were trying to flow out to sea. And, the hearing impaired mocked Manatee County, Florida for using a sign language interpreter that didn’t know sign language. Just in the U.S. alone, 26 people died.

Satellite imagers with higher resolution than VIIRS captured the damage. First, Landsat (~30 m spatial resolution) showed how vegetation was stripped from the soil in Antigua, Barbuda and the Virgin Islands. And, Worldview-4 (~30 cm resolution!) captured images of damaged structures in the Florida Keys and other islands in the Caribbean for Digital Globe (not a paid advertisement or endorsement). Our newest satellite, GOES-16, monitored Irma all the way from birth to death. (Shout out to my collegues at CIRA who provided the imagery used in that article!) And, of course, the VIIRS Day/Night Band showed the extent of power outages in Florida, which I won’t talk about further because I’ve already been beaten to it.

But, VIIRS works during the day, too. And it captured an aspect of Irma’s impact not mentioned above. We’ll start by taking a look at a VIIRS True Color image from 31 August 2017:

VIIRS True Color RGB composite of channels M-3, M-4 and M-5 (1840 UTC 31 August 2017)

VIIRS True Color RGB composite of channels M-3, M-4 and M-5 (1840 UTC 31 August 2017)

Remember, you can click on an image to bring up the full resolution version. Let’s compare this “before” image with one taken after Irma hit:

VIIRS True Color RGB composite of channels M-3, M-4 and M-5 (1813 UTC 12 September 2017)

VIIRS True Color RGB composite of channels M-3, M-4 and M-5 (1813 UTC 12 September 2017)

Notice anything different between the two images?

Apart from all the clouds (which are always different between two images), it shouldn’t take long to notice a change in the water surrounding Florida and, to a lesser extent, the Bahamas. You see, hurricanes bring with them heavy rains, high winds and waves and storm surge. The winds and waves churn up sediment at the bottom of the ocean – like this guy, only more, at least in shallow areas like the Florida Keys and the Bahamas. The storm surge causes beach erosion and flooding along the coasts while the heavy rains cause inland flooding (of both the “flash” and “river” variety). And, when was the last time you saw crystal clear floodwater? Floodwater is filled with dirt from the soils it eroded. Plus, there’s often garbage, raw sewage and toxic chemicals that may make it as hazardous as the hurricane itself. And, let’s not mention floating fire ant colonies because no one want to think about those – except I just did.

If you look closely, you may even see this sediment and pollution beginning to be entrained in currents in the Gulf of Mexico as well as on the Atlantic side of Florida. And, remember that the Atlantic side of Florida is home to the Gulf Stream (the current, not the aircraft).

Of course, we don’t have to just compare two days. We can monitor this sediment and pollution for as long as it’s there. Here’s a video showing both the before image (31 August 2017) and 6 days after (12-17 September 2017):


 
You can view it in full screen by clicking on the icon in the lower right corner of the video. After watching it several times, you should see two things: sediment around the Florida Keys does get pulled into the Gulf Stream, with visible eddies where the polluted water meets the clean water; and the polluted water generally gets darker with time. The latter is due to the fact that more of the dirt and sand and garbage settle out with time, slowly restoring the ocean to its pre-Irma appearance.

You might also notice the ocean around the Bahamas is always lighter in color. This is true even in the “before” image. This is because the water is very shallow in the Bahama Banks, and you can see all the way to the bottom. But, offshore on the west side of the largest island (Andros) the water becomes nearly white after Irma’s passage:

Comparison of VIIRS True Color images before and after Hurricane Irma (2017)

Comparison of VIIRS True Color images before and after Hurricane Irma (2017)

Go back to the video and see that it barely darkens over time. It is possible that, just like flood-induced erosion changes the landscape on the ground, the storm-induced waves and surge may have altered the underwater topography (“bathymetry”) of the Grand Bahama Bank and made the water even shallower. We’ll just have to wait and see how dark it gets.

Postscript: our VIIRS-like geostationary imager, the Advanced Baseline Imager (ABI) on GOES-16 also saw this sediment in the waters off the coast of Florida: click here. Remember, ABI doesn’t have a green wavelength visible band, but that’s no problem for CIRA’s Synthetic True Color imagery! [/end shameless plug]

The Great Flood of 2015

As we begin 2016, struggling to get back into the swing of things at work and vowing not to overeat or over-drink ever again, it’s appropriate to bid farewell to 2015 – not just for all the weird weather events that we covered on this blog over the year, but also for the weird, wacky weather that ruined many people’s holidays. I’m not sure of the exact number, but this article mentions 43 weather-related fatalities in the U.S. in the second half of December. Let’s see, between 23-30 December 2015, there were:

–    77 tornadoes (including 38 on the 23rd and 18 on the 27th);

–    Parts of New Mexico and west Texas got over 2 ft (60 cm) of snow from a blizzard that created drifts upwards of 10 ft (3 m) on the 27th;

–    Record warmth was observed in the Northeast before and during Christmas and the site of Snowvember went until 18 December before the first measurable snow of the season;

–    Chicago received almost 2″ of sleet (48 mm) on the 29th when any accumulation of sleet is quite rare;

–    And – what will be our focus here – St. Louis received over 3-months-worth of precipitation in three days (26-28 December), from a storm that flooded a large area of Missouri, Illinois and Arkansas. In fact, the St. Louis area had the wettest December on record, right after having the 7th wettest November on record, which put it over the top for wettest calendar year on record. Current estimates place 31 fatalities at the hands of this flooding, which caused the Mississippi River to reach its highest crest since the Great Flood of 1993.

What kind of satellite imager would VIIRS be if it couldn’t detect massive flooding on the largest river in North America? (Hint: not a very useful one. Or, a less useful one, if you’re not into hyperbole.) Hey, if it works in Paraguay, it works here – or it isn’t science!

I shouldn’t have to prove that the Natural Color RGB is useful for detecting flooding (since I have done it many, many, many, many, many, many times before), so we can go right to the imagery. Here’s what the Midwest looked like on 13 November 2015 – before the flooding began:

VIIRS Natural Color RGB composite of channels I-1, I-2, and I-3 (19:02 UTC 13 November 2015)

VIIRS Natural Color RGB composite of channels I-1, I-2, and I-3 (19:02 UTC 13 November 2015).

And, here’s what the same area looked like on New Year’s Day:

VIIRS Natural Color RGB composite of channels I-1, I-2, and I-3 (18:45 UTC 1 January 2016)

VIIRS Natural Color RGB composite of channels I-1, I-2, and I-3 (18:45 UTC 1 January 2016).

Notice anything different? This is actually the reverse of the last time we played “Spot the Differences” – we’re looking for where water is now that wasn’t there before, instead of searching for bare ground that used to have water on it.

Of course, the first thing to notice is the large area of snow covering Iowa, Nebraska and northwest Missouri that wasn’t there back in November. Next, we have more clouds over the southern and northern parts of the scene. Those are the easy differences to spot. Now look for the Missouri River in eastern Missouri, the Arkansas River in Arkansas, the Illinois River in Illinois, the Indiana River in Indiana… Wait! There is no Indiana River. I fooled you! (Although, there are rivers in Indiana that are flooded.)

The most significant areas of flooding are in northeast Arkansas and the “Bootheel” of Missouri (which I think looks more like a toe or a claw than a heel), and the Mississippi River along the border of Tennessee shows signs of significant flooding as well. (If only it were the Tennessee River!) Here’s a before and after comparison, zoomed in on that part of the region:

13 November 20151 January 2016

You may have to refresh the page to get this to work right.

There’s a lot more water in the image from 1 January 2016 than there was back in November 2015! Since we are looking at the high-resolution Imagery bands, our quick-and-dirty estimate of water volumes still applies like it did for California’s drought: multiply the number of water-filled pixels by the depth (in feet) of the flooding, and by 100 acres to get the floodwater volume in acre-feet. Then multiply that by 325,852 gallons per acre-foot to get the volume in gallons. Even though this estimate is not exact, you can see how the gallons of floodwater add up. And, if you live in California, you can dream of seeing that much water! If you live in Missouri and can think of an economical way to transport this water to California, you’d be rich.

Now, see how many other areas of flooding you can find when you compare the two images in animation form:

Animation of VIIRS Natural Color RGB images from 13 November 2015 and 1 January 2016

Click to view an animation of VIIRS Natural Color RGB images from 13 November 2015 and 1 January 2016.

You will have to click on the image to see the animation. You can click on the image again to see it in full resolution (with most web browsers).

One thing you might notice is that some of the floodwaters appear more blue than black. Take a look at the Arkansas River in particular. As we discussed with the Rio Paraná and Rio Paraguay, this is due to the increased sediment that increases the albedo of the water at visible wavelengths. In other places the floodwaters are shallow enough that VIIRS can see the ground underneath – again making the water appear more blue in this RGB composite.

Wouldn’t it be nice to identify areas of flooding without having to play a “Spot the Differences” game? Maybe something that would automatically detect flooded areas? Well, you’re in luck:

VIIRS-based Flood Map (18:48 UTC 1 January 2016)

VIIRS-based Flood Map (18:48 UTC 1 January 2016). Image courtesy S. Li (GMU).

This image is an example of the VIIRS-based flood detection product being developed by the JPSS Program’s River Ice and Flooding Initiative. This initiative is a collaboration between university-based researchers and NOAA forecasters who use products like these to help save lives. Thanks to S. Li for developing the product for and providing the image!

If you want to know what the flooding looks like from the ground, here is a nice video. Or, you can look at some pictures here.

As a final note, the American Meteorological Society is holding its Annual Meeting in New Orleans next week. This event will be held at the Convention Center – right on the bank of the Mississippi River – right at the time the river is forecast to crest from these floodwaters. The world’s largest gathering of weather enthusiasts might be directly impacted by this flood. Let’s hope no one has to swim their way to any poster sessions or keynote speeches! (I don’t think local residents want to deal with any flooding, either.)

The Rise of the Paraguay Brings Down Paraguay

When was the last time you heard anything about Paraguay? Nope – they weren’t in the World Cup, that was Uruguay. (Paraguay actually finished last out of all South American teams when it came to World Cup qualifying. Sorry to remind you, Paraguayans.) A quick perusal of the web indicates that the country has a history of isolationism, so it may not come as a surprise that news out of Paraguay is few and far between.

For you non-Paraguayans in the audience: How many of you knew that Paraguay was the richest nation in South America in the mid-1800’s? Paraguay held that title right up to the point that they tried to keep Brazilian influence out of a civil war in Uruguay. That kick-started the War of the Triple Alliance, which ultimately killed more than half the population of Paraguay, strengthened Argentina as a nation, and is credited with bringing about the end of slavery in Brazil. Paraguay has never been the same since. It became the poorest country in the region – a title it has held, pretty much, through today. This has caused one reporter to say (in one of the links above) that, to Paraguayans, success is a prelude to danger.

When the national football team scores, “it makes us nervous and we panic.”

But, this isn’t a metaphor for the title of this post. The title refers to Paraguay: the River (Rio Paraguay), which has brought the worst flooding in decades to Paraguay: the Country, and displaced more than 200,000 Paraguayans. Flooding has also occurred on the Rio Paraná – the second longest river in South America – and has impacted hundreds of thousands of people in Brazil and Argentina. (You won’t get me to say that it has impacted a Brazilian people – because that is an awful, overused joke. Oh, wait. Ignore what I said I wasn’t going to say.)

Just look at what the flooding did to Iguazú Falls – one of the wonders of the world you never heard about – on the border between Argentina and Brazil:

There are more pictures of the flooding at the falls here. Iguazú Falls is located at the head of a narrow canyon called the Devil’s Throat, where water levels were reported to be 16 meters (52 feet) above normal! It is said that this is the worst flooding since 1982-1983. (That flood event killed 170 people.)

As shown before, VIIRS is capable of viewing widespread flooding. So, what does VIIRS tell us about this flood? As it turns out, both the “Natural Color” RGB composite and the “True Color” RGB composite provide unique information, so let’s take a closer look.

If you simply want to see where the water is, look no further than the “Natural Color” RGB composite. The “Natural Color” composite uses the high-resolution bands I-01 [0.64 µm; blue], I-02 [0.87 µm; green] and I-03 [1.61 µm; red]. At these wavelengths, water is not very reflective (it absorbs more than it reflects). So, with low reflectivity in all three channels, water appears nearly black. That allows one to identify water easily. Here’s a Natural Color image from a clear day before the worst of the flooding began (2 June 2014):

VIIRS "Natural Color" image, taken 17:28 UTC 2 June 2014

VIIRS "Natural Color" image, taken 17:28 UTC 2 June 2014

That’s Paraguay in the center of the image. Rio Paraguay is the north-south river that cuts Paraguay in half (OK, maybe 60-40). Rio Paraná is the big river that marks the eastern border between Paraguay and Argentina, and turns south after acquiring Rio Paraguay’s water. (Look for the big reservoir in the upper-right, and follow that river down to the bottom of the image, left of center.) Make sure you click on the image, then on the “3298 x 2345” link below the banner to see the full resolution version. Compare that with a similar image from the only clear day at the end of the month (30 June 2014):

VIIRS "Natural Color" image, taken 17:03 UTC 30 June 2014

VIIRS "Natural Color" image, taken 17:03 UTC 30 June 2014

At first glance, the most obvious flooding occurred along the Paraná in Argentina. But flooding is noticeable along the Rio Paraguay if we zoom in for a closer look. Here’s a “before” (2 June) and “after” (30 June) overlay for the area around Paraguay’s capital city, Asunción:

Drag the vertical bar over the images from left to right to compare the two. (If this “before/after” trick doesn’t work for you, try refreshing the page. It may not work at all if you’re using Google Chrome.) The flooding you see here near Asunción was associated with only a 2 m (6 ft) water rise.

Something interesting happens when we focus in on the Paraná at the Itaipú Reservoir, just upstream from Rio Iguazú:

VIIRS "Natural Color" images of Itaipu Reservoir, June 2014

VIIRS "Natural Color" images of Itaipu Reservoir, June 2014. These images have been brightened to highlight difference in reservoir color.

After the flooding, the reservoir no longer appears black. This is because the flooding washed an awful lot of dirt into the water. And it really shows up in the “True Color” RGB composite:

VIIRS "True Color" images of Itaipu Reservoir, June 2014

VIIRS "True Color" images of Itaipu Reservoir, June 2014.

The water appears more turquoise before the flood, and brown after the flood. This is because the True Color composite represents the true color of the objects in the image. It is made from channels in the blue [0.48 µm; M-3], green [0.55 µm; M-4] and red [0.67 µm; M-5] portions of the visible spectrum. Take a look again at the Iguazú Falls video above and notice how brown the water is. The True Color images capture this. The reason the water appears blue and not black in the Natural Color composite is that there is enough sediment in the water to make it reflective at 0.64 µm (the blue component of the image). The longer wavelengths in the green and red components are not sensitive to the sediment, whereas the shorter wavelengths in the True Color components are very sensitive to sediment. (This is the basis for Ocean Color retrievals.)

If we focus in on the Rio Paraná near where it meets the Rio Paraguay, we can see clearly that the Natural Color highlights where the flood waters are, and the True Color highlights the sediment in that water:

VIIRS Natural Color and True Color images of the Rio Parana, June 2014

VIIRS Natural Color and True Color images of the Rio Parana, June 2014

Unfortunately, floods on the Paraguay and Paraná rivers are not uncommon, as a resident of Asunción explains:

BONUS: The NOAA/STAR JPSS group has put together a website on the flooding in Paraguay that features my Natural Color images along with a number of other VIIRS-based products that are being developed for flood detection. A lot of people from a number of different research groups played a part in this!

Record Russian Rain Runoff Responsible for Rapid River Rise

Sorry, I couldn’t help myself with that title.  Last time we looked at flooding in Russia, it was in the western parts – generally near Moscow and primarily along the Oka River – and caused by rapid melting of record spring snowfall. This time, flooding is occurring in Russia’s Far East, primarily along the Amur River, caused by heavy rainfall related to monsoon wind patterns in the region – record levels of flooding not seen before in the 160 years Russians have settled in the area.

Unfortunately, this natural disaster is affecting more than just Russia. In China, many people are dead or missing as the result of flooding. (The figure of “hundreds dead or missing” includes flooding caused by typhoons Utor and Trami in southeastern China, flash flooding in western China, and the subject of today’s post: river flooding in northeastern China and far east Russia.) The Chinese provinces of Liaoning, Jilin and Heilongjiang have been hit particularly hard with persistent, heavy rains since late July, as have areas just across the border in Amur Oblast, Khabarovsk Krai and the Jewish Autonomous Oblast in Russia.

A few more facts: Heilongjiang is the Chinese name for the Amur River. It translates to English as “Black Dragon”. The Mongols called it Kharamuren (“Black Water”), which, I assume, the early Russian settlers shortened to Amur. It is the longest undammed river in the Eastern Hemisphere and the home to the endangered Amur leopard and Amur tiger. Since 1850, the Amur River has been the longest piece of the border between China and Russia. Now, in 2013, the Amur River has reached the highest levels ever recorded.

Backing up a bit, here’s what the area looked like according to “Natural Color” or “pseudo-true color” VIIRS imagery back in the middle of July:

VIIRS false-color RGB composite of channels I-01, I-02 and I-03, taken 03:27 UTC 14 July 2013

VIIRS false-color RGB composite of channels I-01, I-02 and I-03, taken 03:27 UTC 14 July 2013

As always, click on the image, then on the “2368×1536” link below the banner to see the full resolution version. Here’s what the same area looked like about a month later:

VIIRS false color RGB composite of channels I-01, I-02 and I-03, taken 03:14 UTC 21 August 2013

VIIRS false color RGB composite of channels I-01, I-02 and I-03, taken 03:14 UTC 21 August 2013

Notice anything different? The Amur River has overflowed its floodplain and is over 10 km (6 miles) wide in some places. Just downriver (northeast) from Khabarovsk, the flooded area is up to 30 km (18 miles) wide!

Pay attention to Khabarovsk. Back in 1897, the Amur River crested there with a stage of 6.42 m (about 21 feet in American units), which was the previous high water mark. On 22 August 2013, the river stage reached 7.05 m (23 feet) and was expected to keep rising to 7.8 m (25.6 feet) by the end of August. The map below (in Russian) shows the local river levels on 22 August 2013. It came from this website.

Amur River levels at various locations in Khabarovsk Krai, Russia on 22 August 2013.

Amur River levels at various locations in Khabarovsk Krai, Russia on 22 August 2013.

Note that Khabarovsk in Cyrillic is Хабаровск (the black dot in the lower left), and Amur is Амур. The blue numbers represent the river stage in cm. Red numbers indicate the change in water level (in cm) over the last 24 hours. The colored dots indicate how high the river level is above flood stage according to the color scale (also in cm). The river at Khabarovsk is more than 4 meters (13 feet) above flood stage.

Not impressed by comparing a “before” and “after” image? Here’s an animation over that time period (14 July to 21 August 2013), with images from really cloudy days removed:

Animation of VIIRS false-color composites of channels I-01, I-02 and I-03

Animation of VIIRS false-color composites of channels I-01, I-02 and I-03. Click on the image, then on the "1184x768" link below the banner to view the animation.

You have to click through to the full resolution version before the loop will play. In order to not make the world’s largest animated GIF, the I-band images in the loop have been reduced in resolution by a factor of 2, making them the same resolution as if I had used M-5, M-7 and M-10 to make this “Natural Color” composite.

The Day/Night Band is not known for its ability to detect flooding at night, but it also saw how large the Amur River has become:

VIIRS Day/Night Band image, taken 17:27 UTC 20 August 2013

This image was taken on 20 August 2013, which just so happens to be the night of a full moon. The swollen rivers are clearly visible thanks to the moonlight (and general lack of clouds).

Khabarovsk is a city of over 500,000 people and would require a major evacuation effort if the river reached the expected 7.8 m level. Over 20,000 people have already been evacuated in Russia alone (and over a million people in China) according to this report. Oh, and at least two bears.

This heavy rain and flooding makes it all the more surprising that, a little further north and west in Russia, there have been numerous, massive wildfires. Check out this “True Color” image from VIIRS, taken on 16 August 2013:

VIIRS"True Color" composite of channels M-3, M-4 and M-5, taken 03:12 UTC 16 August 2013.

VIIRS"True Color" composite of channels M-3, M-4 and M-5, taken 03:12 UTC 16 August 2013.

See the supersized swirling Siberian smoke spreading… OK, I’ll quit with the alliteration. Here’s the smoke plume on the very next overpass (about 90 minutes later) seen on a larger scale:

VIIRS "True Color" composite of channels M-3, M-4 and M-5, taken 04:52 UTC 16 August 2013.

VIIRS "True Color" composite of channels M-3, M-4 and M-5, taken 04:52 UTC 16 August 2013.

A strong ridge of high pressure with its clockwise flow is trapping the smoke over the region. In this image you can see quite a few of the smoke sources where the fires are still actively burning. Look in the latitude/longitude box bounded by 98 °E to 105 °E and 59 °N to 61 °N. By the way, that’s Lake Baikal on the bottom of the image, just left of center.

A quick back-of-the-envelope calculation indicates that the area covered by smoke is roughly 500,000 km2. (Of course it is complicated by the fact that the smoke is mixing in with the clouds, so it is hard to define a true boundary for the smoke on the north and west sides.) That puts it in the size range of Turkmenistan, Spain and Thailand. If that’s not a good reference for you, how’s this? The smoke covers an area larger than California and smaller than Texas.

These fires have burned for more than a month. This article from NASA includes a MODIS image from 25 July 2013 containing massive smoke plumes and shows that areas of central Russia (particularly north of the Arctic Circle) have had a record heatwave this summer. And here are a few more images of the smoke from MODIS over the past few weeks.

Heatwaves and fires and floods? Russia is all over the map. Literally. I mean, look at a map of Asia – Russia is all over that place. It even spreads into Europe!

Record Russian Spring Snowmelt

It seems that last year’s posts were all about fires. Fires in Colorado (multiple fires, in fact), the Canary Islands, Siberia, Australia – there was even that 40-year-old pit of burning natural gas that has been called the “Gates of Hell“. (It’s still burning, by the way.) Maybe this year’s theme will be all about flooding. We just looked at flooding in the U.S. Midwest. And now, we return back to Russia – the western part this time – where massive flooding has occurred this spring.

Moscow had 65 cm of snow on the ground on 1 April 2013. (That’s roughly 26 inches for any American readers.) That’s the most snow they’ve ever had on the ground that late in the spring, and it was all thanks to record snowfall during the month of March. This article from 26 March 2013 says they got 70 cm (28 inches) in a two day period, and forecasters were predicting another 8-10 cm by the end of the month.

What happens when record amounts of snow melt? It causes flooding. In this case, flooding that makes the Illinois River look like a creek you can hop across. The watershed of the Volga River has been hit especially hard. Here’s a picture that our resident Russian, Galina C., tells me is from near the city of Ryazan, so I assume it is the Oka River. (Refer back to the Volga River map I linked to.) There are more pictures here.

To bring this all together with VIIRS, here is what VIIRS saw on 28 March 2012, right after the region got 70 cm of snow:

False color RGB composite of VIIRS channels I-01, I-02 and I-03, taken 10:38 UTC 28 March 2013

False color RGB composite of VIIRS channels I-01, I-02 and I-03, taken 10:38 UTC 28 March 2013

Again, to see the full resolution image, click on it and then click on the “1793×2036 ” link below the banner. This is the false color combination that EUMETSAT refers to as “Natural Color“, where snow and ice appear cyan and liquid clouds appear white. The whole scene is snow, except for a few small clouds north of Moscow and anywhere there are trees sticking out above the snow, which appear green.

Notice that you can’t see any rivers. They’re all frozen over and covered with snow.

Here’s what VIIRS saw (same false color combination) a month later (29 April 2013):

False color composite of VIIRS channels I-01, I-02 and I-03, taken 10:39 UTC 29 April 2013

False color composite of VIIRS channels I-01, I-02 and I-03, taken 10:39 UTC 29 April 2013

All the snow is gone. Plus, look at all the rivers you can see. The problem is that you shouldn’t normally be able to see all of these rivers. The flooding makes them visible.

What I think is more impressive is seeing a time-lapse loop of VIIRS images over this period:

Animation of false color composites of VIIRS channels I-01, I-02 and I-03 from 28 March 2013 to 2 May 2013.

Animation of false color composites of VIIRS channels I-01, I-02 and I-03 from 28 March 2013 to 2 May 2013.

Make sure you look at it in full resolution mode. Note that the time period between frames in the animation varies. Some days it was too cloudy to see anything, one or two days had missing data, etc., so this isn’t always one image per day.

The city of Ryazan is identified in the animation (remember the photo linked to earlier). To put it into perspective, check out the Google Maps satellite view of the city. The Oka River is normally ~200 m wide near the city. In the last two frames of the animation, the Oka River is over 10 km wide at its widest point near Ryazan! The same goes for a lot of the rivers visible at the end of the loop – rivers that are normally a few tens or hundreds of meters wide are up to a few kilometers wide.

The city of Tambov at 52°43′N, 41°26′E, which is outside of the domain of the animation, but in the southeastern portion of the larger static images, experienced its worst flooding in 130 years in early April. (That corner of the domain was the first to experience snowmelt.) One of the contributing factors at Tambov, according to that article, was that the ground below the snow was still frozen. The snowmelt occurred before the ground thawed. This meant that the meltwater couldn’t be absorbed into the ground – it simply collected in the low-lying areas or ran off into the rivers, which quickly filled as you can see.

Our resident Russian was also able to grab this plot of the Oka River stage at Novinky, just upstream of where the Oka empties into the Volga. The information comes from this website. This plot covers the time period from 7 April to 7 May 2013.

River stage of the Oka River at Novinky, Russia for April 2013

River stage of the Oka River at Novinky, Russia for April 2013. Data comes from gis.waterinfo.ru, with help from Galina Chirokova (CIRA).

The Oka River looks like it peaked at about 2.5 m above normal. (8 ft. for you Americans.)

All that water is going to end up in the Caspian Sea, whose water level is largely based on inflow from the Volga River’s watershed. Variations of sea level in the Caspian have been +/-3 m over the last century and, with this influx of snowmelt, it is sure to go up.