Floodwaters continue to rise in Russia’s Orenburg Region after dams burst along the River Ural earlier this week. According to the region’s governor, the water levels in its capital city Orenburg have risen to more than ten metres.

The region’s second largest city of Orsk has been particularly badly struck by the floods. A small number of residents took to the streets on Monday in a rare protest against the government. They demanded compensation, accusing authorities of mishandling the evacuation of residents and disputing officials’ claims that residents were notified of the situation before protective embankments were breached in the flood.

The Ural River lies in Russia’s Ural Mountain range and passes through several Russian cities before entering Kazakhstan and emptying into the Caspian Sea. Authorities of both countries have declared states of emergency and approximately 120,000 people have been evacuated from their homes. Climate experts told Reuters that heavy snowfall followed by a swift rise in temperatures contributed to this year’s large floods.

With open source information we can piece together some of what happened in Orsk and across the Orenburg Region, showing the extent of Russia’s worst flooding in decades and the inability of flood protection systems to withstand the surge. 

For example, the comparison slider below shows satellite imagery of the old city of Orsk on October 9, 2021 and on April 10, 2024. The streets of the old city (in the centre) are submerged beneath brown floodwaters, as are allotments and agricultural land (upper left).

Not all satellite imagery is so clear. This is where Sentinel-1 Synthetic Aperture Radar (SAR) is useful. If a regular optical satellite collects images by registering the light from the sun which reflects off the earth, SAR functions as its own ‘sun’ by emitting signals and registering what is reflected back to them. This allows SAR to ‘see’ through cloud cover – a definite advantage when tasking satellite imagery in winter or spring. Bellingcat has therefore used SAR to investigate issues from Russia’s grain smuggling fleet to the movements of Equatorial Guinea’s ruling family.

Commonly, objects which reflect SAR very intensely will appear on the resulting image with brighter colours. Objects which absorb rather than reflect SAR emissions appear with darker ones – this includes water.

On April 8 at 02:16 local time, the European Space Agency (ESA)’s Sentinel-1 SAR took a satellite image of Orsk and the surrounding area. The extent of the flooding can be clearly seen in black in the image below. This black area was overlaid onto a true colour satellite image from ESRI, which is a composite of imagery from different recent dates within a limited range.

Data from Open Street Map was then added for further context, showing the area’s major roads in yellow and Russia’s border with Kazakhstan in red.

High resolution SAR imagery from Umbra showed the flooding in greater detail. Once again, the black areas show an object with a very low SAR return signal — water.

SAR captures from April 9 showed how some riverside communities were completely submerged.

For example in Novotroitsk, a suburb downstream from Orsk, smaller houses closest to the river had disappeared underwater by April 9, while the city proper appeared above water. The comparison slider below overlays Umbra SAR imagery (in the black and white square) onto an ESRI composite image of the same area from early 2024.

Floodwaters surged through Orsk after protective embankments burst. These earth ramparts, which snake across the landscape, are common parts of flood management systems designed to direct water away from areas of human settlement.

How these embankments collapsed has been a source of some dispute – experts told the local news website Orenburg Media that an earth embankment near Orsk’s old town was only designed to hold back five and a half metres of floodwater. Poor construction quality has also been considered; on April 6 the Investigative Committee of Orenburg Region opened an investigation into criminal negligence on the issue.

“The dam which is being discussed in Orsk isn’t actually a dam. A dam doesn’t cost a billion rubles, 10 kilometres wide… This dam withstood around five and a half metres [of water] but then we got ten. With incredible speed, a huge mass of water surged not towards a dam, but an earthen rampart”, said Russia’s Minister of Construction Irek Fayzullin on April 11.

Satellite images and social media posts reveal that the embankments protecting Orsk broke in at least six areas. These locations are represented by yellow pins in the satellite image below. The white pin is the location of a visit which the Mayor of Orsk Vasily Kozupitsa made to one of the embankments shortly before the floods.

Note that the numbers do not represent the chronological order of the breaches:

Water can be seen flowing through the breach in photographs published by Ural56 on April 6 and independent media outlet Meduza on April 7.

The embankment at Location Two (51.238843, 58.581747) was near Borisoglebskaya Street in the industrial suburb of Nikel, to the east of Orsk’s old town. It was reported to be breached on April 6.

The gif image below shows the intact embankment on September 21, 2023 and its condition by April 10, 2024.