The state Environment Agency (Keskkonnaagentuur) has explained how exceptionally heavy rain led to severe flooding in the South Estonian town of Tõrva on Thursday, though neither the rainfall nor river levels ultimately proved unprecedented, Maaleht reported.
Heavy rain triggered severe flooding in the Tõrva area in Valga County on Thursday morning, with initial reports saying a dam had been inundated, in turn leading to structural damage to nearby properties. This necessitated the evacuation of at least eight people.
The Tõrva hydrometric station is sited about 30 meters downstream from the Tõrva bridge. Ahead of torrential rain starting Wednesday, river levels were normal and even relatively low, though soon after the heavy rain they steadily started to rise, peaking on Thursday at 265 centimeters above the station's zero level.
A total of 56 millimeters of rain fell on July 8-9, nearly 80 percent of the area's average rainfall for the entire month of July, while as of Friday rainfall in July is already 119 percent of that average, with over three weeks of the month to go.
When a very large amount of rain falls in a short period, the ground cannot absorb all the water quickly enough and the excess flows rapidly into rivers and streams, causing water levels to rise sharply, as here. Following the peak flooding on Thursday, the water level gradually began to subside.
Surprisingly, despite the intensity, the water level high was not a record for Tõrva—that was set on the same date, July 9, but way back in 1978 and at a much higher level, 458 centimeters above the station's zero level.
Even the rainfall total was not unprecedented. A higher daily total was recorded just two years ago, when 80.6 millimeters fell in Tõrva on July 29, 2024, and daily rainfall values of 50 millimeters or more are seen in Tõrva on average once every five to six years. In the 76 years since records began, there have been 12 such days in total.
A low-pressure system that formed over southern Sweden on Tuesday evening was the culprit, and its southern flank drew in abundant moisture from the Atlantic in a strong west-northwesterly flow. Cool air lay on the system's northern side, while midsummer levels of warmth prevailed to the south, which provided the energy for the cyclone to intensify.
The next day the low-pressure system reached the Lithuania-Latvia border, bringing heavy rain, which then spread into southern Estonia, where Tõrva is located, along its edge.
Mayor: Crisis meeting held; psychological support available
Recovery work is in full swing, Mayor Kalle Vister (Isamaa) later told Maaleht following a crisis meeting, adding both drinking water and sewer services were restored on Thursday afternoon and evening, "thanks to the additional personnel and equipment we brought in," the mayor said.
While most of the floodwater has already been removed from the affected properties, restoration work is only beginning, Vister noted.
"Next week, volunteers will help clean up the yards and work on the affected properties," he added.
As for those left temporarily homeless: "We offered one family accommodation and meals at a care home. We also offered temporary social housing, which the social services department quickly found, but they did not wish to use it. Some went to stay with acquaintances," Vister said.
When it comes to restoring homes and compensating for damage, the initial hope is primarily that homeowner insurance will cover the costs, he said, adding it is not yet known if and to what extent the state might be able to help.
Pastoral support is also on hand, the mayor said. "As of today, we are ready to provide psychological support if they need it. At the moment, people are generally positive, but once a person has time to process what happened, they may experience anxiety or other difficulties. We have ensured that this support is available," the mayor said.
The municipality now says the dams themselves remained intact and were not breached as initially reported; the collapse of natural ground next to the Tikste dam instead had carved breaches, "allowing the water to carve out a channel," Vister said.
Work is now focused on securing the area and restoring the reservoir.
Once the Tikste valley is filled with gravel, crews can clear mud from the dam area, redirect the reservoir back into its channel, and reinforce the nearby residential area to help prevent a repeat, Vister added.
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Editor: Andrew Whyte
Source: Delfi