‘Significant’ Rainfall Expected as Seattle Reservoirs’ Water Levels Fall

Significant rainfall is expected in the Seattle area this weekend after the region struggled with a dry summer that has contributed to falling levels at two of its reservoirs.

As of Tuesday, Seattle rainfall is more than 5 inches below its annual average, National Weather Service (NWS) meteorologists said. October is the start of Seattle’s wet season, though, and as much as 6 inches of rain is forecast across parts of the Seattle forecast region this weekend, which could add a boost to the city’s annual rainfall totals.

“Graphic with the forecasted rain totals today through the weekend,” the NWS office in Seattle posted on X (formerly Twitter) on Wednesday morning. “System over the weekend could bring significant rainfall to the area. 2024 rain total at Seattle-Tacoma airport 19.61″, 5.29″ below normal. 19.61″ thru Oct. 15th is the 3rd driest total in last 30 years.”

As dry weather took hold this summer, two Seattle-area reservoirs have experienced falling water levels since June. As of the most recent measurements, Chester Morse Lake near Cedar Falls was at 1,547 feet, nearly 20 feet below its June levels. Tolt Reservoir near Carnation, Washington, was at 1,740 feet, roughly 15 feet below its June levels.

Despite the dry season, both reservoirs are performing better than they were during this time last year. In September of last year, Seattle Public Utilities (SPU) asked its customers to conserve water, citing an unusually dry summer as the reason for its concerns.

By December of that year, both reservoirs had recovered.

Tolt Reservoir provides about one-third of the drinking water for the region, SPU said. Chester Morse provides two-thirds.

“We have been drier than normal, but we are starting to transition into that period of more rainfall,” NWS meteorologist Samantha Borth told Newsweek. More rain in October is “pretty typical for fall” in the area, she said. “We have been dry, but that’s looking to change this week.”

Borth said the falling levels at both reservoirs were likely related to the limited rainfall this summer.

Despite heavy rain amounts this week and into the weekend, Borth said, the Seattle region isn’t expecting any floods.

The most recent U.S. Drought Monitor map shows that more than 9 percent of Washington was battling severe drought. More than 42 percent was struggling with moderate drought, and more than 76 percent of the state was considered abnormally dry. Despite the drought, Washington is in a better situation than this time last year, according to the map.

Winter weather has arrived elsewhere in the U.S., causing heavy snow in Montana and a series of frost advisories and freeze warnings across the nation.