Today’s rainfall pushed the March precipitation total to the third highest on record, according to the National Weather Service.
Spokane International Airport also measured a record 0.62 inches for the day through 5 p.m., surpassing the old record of 0.53 inches in 1943.
So much rain fell in the region that the National Weather Service this morning issued a flood warning for the Palouse region of Washington and North Idaho after steady rain fell throughout the night and morning hours.
Small streams, including tributaries of the Palouse River, are at risk of overflowing. In addition, ponding water is likely in urban areas, forecasters said.
The counties affected by the warning are Whitman, Asotin and Garfield counties in Washington and Latah, Nez Perce and Lewis counties in Idaho.
Spokane recorded 0.62 inch of through 5 p.m. today, pushing the total for the month to 3.31 inches. That eclipses last March when 3.25 inches fell. The wettest March was in 1995 at 3.81 inches.
A moist southerly flow is colliding with an elevated cold front in Eastern Washington, causing higher than normal amounts of precipitation.
Pullman-Moscow Regional Airport had 0.8 inches of rainfall by 10 a.m. after the rain started about 10 p.m. on Sunday.
Spokane International Airport has reported a third of an inch of rain through 11 a.m. with moderate rain falling at mid-morning. A total of 0.13 inches fell from 10 to 11 a.m.
The airport reported light snow at 11 a.m.
If rain continues, it could cause lower elevation snow pack to melt off and send the Palouse River over its banks, forecasters said. The area around Potlatch is at risk, they said.
The Palouse River at Potlatch was flowing at 3,430 cubic feet per second today, which is well above the average of 646 cfs for this time of year.
The South Fork of the Palouse River at Pullman was flowing at 1,260 cfs today, which is way above the average of 60 cfs for this time of year.
Also, Asotin Creek at Asotin was flowing about four times its normal volume at 270 cfs.
Rain is expected to subside by tonight, forecasters said, but more rain and showers are expected by later on Tuesday and continuing through the week. Highs should reach the lower 50s with lows in the 30s.