Storms to chill heat wave

As Inland Northwest temperatures soared into the 90s for the fourth day in a row on Thursday – sending even more snowmelt into the area’s raging rivers – forecasters turned their attention to a new threat: the potential for thunderstorms tonight.

The National Weather Service Thursday issued a hazardous weather outlook warning of heavy rain as a potential thunderstorm system crosses the region later today through Saturday morning.

Forecasters said the storms will mark the end of an unusual May heat wave that saw high temperature records broken repeatedly.

The heat also unleashed torrents of water previously locked in the high-mountain snowpack, sending numerous rivers over their banks and forcing closures of two forest roads, one forest campground and two public fishing access sites.

“Our little sneak peek of summer is coming to an end,” said hydrologist Charles Ross of the weather service office in Spokane.

On Thursday, Spokane broke a 52-year-old record with a high temperature of 90 while Coeur d’Alene tied its previous record of 90. For both cities, it was the third-straight day of record heat.

Highs today were expected to reach 80 degrees in Spokane and 79 in Coeur d’Alene, and fall by a few more degrees to the mid- to upper-70s on Saturday and Sunday.

Lower temperatures, in most instances, would slow the flooding danger from fast-melting snow, except that the threat of heavy thunderstorms could send even more water into the region’s swollen rivers, Ross said.

Ross gave the following flood update:

“The Kootenai River at Bonners Ferry is expected to reach flood stage by this weekend, sending excess water across low-lying farm fields.

“The Moyie River at Eastport is expected to reach flood stage, or rise to just under flood stage this weekend.

“The Methow River in northern Washington was flooding Thursday over its entire length and was expected to crest late tonight about one foot above flood stage.

“The Entiat River in Chelan County was flooding, and the sheriff there was reportedly asking some residents to evacuate.

Also at or near flood stage were the Naches, Wenatchee, Stehekin and Okanogan rivers in Washington. High flows are expected on the Pend Oreille, Snake, Clearwater, Coeur d’Alene, Similkameen, Spokane and St. Joe rivers. High water on the Bitterroot River in Western Montana forced closure of two fishing accesses near Hamilton.

Lake Coeur d’Alene has been rising, but Ross said it should stop at an elevation of 2,128.5 feet, which is just above the level at which Avista Corp. holds the lake during the summer through its regulation of flow at Post Falls Dam.

Ross said that most of the snow in the mountains above Lake Coeur d’Alene has melted, but with so much runoff still draining through the lake, the thunder of the Spokane Falls will be heard for weeks to come.