The worst of the region’s flooding may be headed to sea by now.
High water will continue on some rivers for several days, but forecasters said the faucet is getting turned off. Most rivers will crest or start dropping today.
Drier weather will take over. No new storms are expected, and highs should be in the upper 30s to mid 40s.
“We’re seeing the end of it now,” said Spokane meteorologist Ron Miller.
What a wild week it’s been.
The dramatic swing from snow to Arctic cold to rain set the ideal stage for Northwest flooding.
Upper-level winds pushed last week’s record-setting freeze down from northern Canada, only to be replaced by a strong surge of moist air off the subtropics of the Pacific Ocean.
The change brought a 60- to 70-degree reversal in the thermometer and triggered a big meltdown.
That mild air carried copious amounts of moisture.
Pullman had nearly 2 inches of rain in two days. Walla Walla, which recorded a high of 67 Thursday, had an inch.
Frozen ground did little to absorb any of the runoff, and the mild rain served only to speed the snow melt.
In the past 50 years, only the spring flood of 1948 was worse.
That disaster destroyed a wartime city of Vanport near Portland, caused widespread damage throughout the region and left three dozen dead or missing.
Understanding the cause of wintertime floods takes a grasp of the wind patterns at 18,000 feet or higher. Normally they flow from west to east in the northern latitudes, but occasionally develop sharp swings to the north or south.
The Arctic cold comes when the jet stream flows out of the polar regions, and the warm rains occur when the pattern shifts blow off the warm waters near Hawaii. When those patterns occur back-to-back, especially after a lot of snow has fallen, floods are almost certain in the Northwest.El Nino subsided last spring, and shows no signs of returning.
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