Flooding potential for 2018
Many folks have enjoyed the recent weather pattern of sunshine and high temperatures in the 70s. On Friday, May 4, it was another pleasant afternoon as Cliff reported a high of 77 degrees. Saturday’s high was a comfortable 74 degrees. On Sunday, mercury topped out at 83 degrees. The normal highs are in the mid-60s.
The warmer than normal temperatures will also increase the snowmelt in the higher mountains, which can increase the risk for flooding. At Silver Mountain, there is still over 90 inches of snow in the ground. At Lookout Pass, there is about 140 inches at the summit.
Most of the time, the Inland Empire sees its greatest risk of high waters during the spring season. The big floods typically result from torrential thunderstorm downpours plus warm rains falling on melting snowpacks in the higher elevations. Much of the flooding generally occurs in the foothills of the Cascade Mountains, in the highlands of northeastern Washington as well as across portions of northern Idaho and western Montana.
Historically, northern Idaho and the rest of the Inland Empire has seen its share of high waters. There was also a big flood in 1918, exactly 100 years ago in Coeur d’Alene. According to an article by the Spokane Daily Chronicle, the Coeur d’Alene River went over its banks and destroyed every bridge from Cataldo to Harrison.
In November of 1990, there was widespread major flooding on western Washington rivers, especially the ones in the northwest and several eastern Washington rivers. The Interstate 90 Lake Washington floating bridge actually sank during that time. Two deaths were recorded as damage was estimated at $250 million.
There was widespread flooding in February 1996 in Washington, Oregon and Idaho. The rivers across the region went far above flood stage due to a “rain-on-snow” event combined with ice jams in area rivers. Temperatures were near zero degrees at the end of January, which led to ice along many rivers along with deep snows. The most severe flooding occurred on the Coeur d’Alene River basin, the St. Joe River basin and the Palouse, Orofino and Lapwai creeks. The overall damage in the region was estimated at a staggering $800 million.
At Cataldo, the flood stage along the Coeur d’Alene River is 43 feet. In February of 1996, the river went to 51.62 feet. The highest level ever recorded at Cataldo was in January 1974 when the river rose to 58.23 feet.
Perhaps the worst flood ever seen in recent times across our region happened in May and June of 1948, known as the “Greatest Spring Snowmelt Flooding.” During that time, there was widespread flooding in northern Idaho and eastern Washington, especially along the Columbia River. Below Priest Rapids, Washington, the Columbia River topped at 458.65 feet, an all-time record. Flood stage is 432 feet. At Lake Pend Oreille near Hope, a crest of 2071.2 feet was measured with a flood stage of 2063.5 feet. Methow River at Pateros, Wash., hit 12.30 feet with a flood stage of only 10 feet. At the St. Joe River at Calder, a record 18.10 feet was seen.
Readings since late last week have been climbing into the 70s. More 70-degree weather is expected over the next few days, but highs should be a little cooler toward the end of the week.
Cliff and I see a pattern of occasional showers and thunderstorms through late May or into early June. There will also be plenty of days with sunshine and warm afternoons. Then, we see a much warmer and drier summer season across the Inland Northwest, but not as dry as last year.
With temperatures warming up to above normal levels, as much as 10 to 15 degrees, the snow in the higher mountains will be melting at a faster pace. The National Weather Service has already issued flood warnings along the Okanogan River in Washington. The Moyie River in Boundary County is currently under a flood watch. It’s possible the flood watches and warnings could expand, especially if we see some heavy rainfall later in the month.
Temperatures for the rest of the week will be cooler with readings in the 60s and 70s. Tuesday’s high could be close to 80 degrees.
In case you haven’t heard, there is a contest for the first 90-degree day in Coeur d’Alene. Give us your guess and you’ll have the chance to win up to $700 of gift cards from area restaurants and food servers.
The contest is located at www.cdacontest.com. It will run until May 31, or when our first 90-degree temperature is hit. But, you only get one guess per email address. (By the way, I promise that email address will not be shared or sold.) As always, our temperatures will be monitored by Coeur d’Alene’s long-time climatologist, Cliff Harris. He will provide the exact date and time when Coeur d’Alene hits 90 degrees (89.5 degrees).
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Contact Randy Mann at randy@longrangeweather.com