Olympia area smashes rainfall record for Dec. 8. More rain is on the way

A record-breaking amount of rain fell in the Olympia area on Monday and more rain is on the way, according to the National Weather Service.

The rain and windy weather has triggered a flood warning for the area through Tuesday night, a wind advisory has been extended through Wednesday and a flood watch in still in effect for the remainder of the week, the NWS has announced.

Meanwhile, 3.03 inches of rain fell between midnight Monday and midnight Tuesday in the Olympia area, smashing a 10-year-old record, said NWS forecaster Matthew Cullen.

The old record was 2.50 inches of rain, which fell Dec. 8, 2015, he said.

And more rain is on the way. Another two inches of rain is expected to fall from Tuesday night through Wednesday, followed by about a half-inch of rain later in the week, Cullen said.

Although that isn’t as much as Monday’s rainfall, the concern is that the additional rain will increase the risk of more flooding, he said.

“Rivers and creeks are running much higher and won’t have time to recede,” said Cullen.

Some agencies have taken steps to address the rainfall.

According to Thurston County Emergency Management, Tacoma Power announced Monday night that it would increase the flow of water from the LaGrande Dam on the upper Nisqually River, which empties into Puget Sound in Thurston County.

The flow rate was increased to 9,000 cubic feet per second from 2,400 cubic feet per second until Tuesday morning, according to Thurston County.

“Minor flooding occurs when the flow rate at LaGrande Dam exceeds about 8,000 cubic feet per second,” the county information reads. “Although no residential structures are threatened at this flow rate, farms and pastureland upstream from the head of the Centralia Power Canal experience enhanced bank erosion.”

The Centralia Power Canal is in an area near Yelm.

The Skookumchuck River in south Thurston County also flooded a part of state Route 507 near the town of Bucoda Monday night, according to the state Department of Transportation.

Water was reported over the road about 9:30 p.m., but it receded about an hour later, WSDOT officials said in an alert.

Area rivers to keep an eye on: Nisqually, Deschutes, Skookumchuck and the Chehalis River, which flows past south Thurston County.

The National Weather Service issued a wind advisory over the weekend. Gusts were expected as high as 45 miles per hour in the area, but ultimately reached about 25 miles per hour, according to recordings at Olympia Regional Airport.

Those winds produced only scattered power outages, according to Puget Sound Energy data, which shows about 4,200 customers affected throughout its service area as of Tuesday.

The risk of outages remains, however, because the current wind advisory forecasts wind gusts up to 40 miles per hour, Cullen said.