Rain and snow melt today forced Spokane police to close the intersection of Sunset Boulevard and Government Way, and melt water was encroaching on many other streets.
A flood watch was upgraded to a flood warning today by the National Weather Service for the Spokane area along with Whitman, Garfield and Asotin counties in Washington and Kootenai, Benewah, Latah and Nez Perce counties in Idaho.
Forecasters concerned about the weight of the region’s snowpack on roofs said today that records show that this month’s snow load may be below the amount of weight at the peak of last winter’s storms.
On Monday, the weather service measured 4.2 inches of water in the snowpack compared with 5.1 inches of water last February. The heaviest snow pack apparently was in February 1969 when 6.9 inches of water was measured in the snow.
Each inch of water weighs about 5.2 pounds per square foot, making the current snow load on the ground about 22 pounds per square foot. Roofs in Spokane are required to hold 30 pounds per square foot, and residential roofs are capable of holding more. The 1969 snowpack weighed about 36 pounds per square foot.
In the Spokane region, a hazardous weather outlook was in effect today for a combination of snow and rain in the urban areas.
Rainfall in combination with snowmelt could create urban and small stream flooding, according to the National Weather Service.
The rainfall is expected add to snow loads on roofs, officials said. A little more than an inch of rain was expected to fall in Spokane through Thursday afternoon, with 1.8 inches expected in Coeur d’Alene and 1.85 inches in the Silver Valley of North Idaho.
Forecasted rainfall through Thursday could challenge normal roof design limits, said Sandy Von Behren, emergency manager for Kootenai County Office of Emergency Management.
Peak snow loading on roofs in Coeur d’Alene will happen Wednesday night into Thursday, Von Behren said. “Shoveling all or some of the snow off roofs will relieve the loading.”
Residents should also make sure drains are clear of ice so water can drain.
It’s important to use the buddy system when shoveling roofs, Von Behren said.
Meanwhile, total snowfall in Spokane was 78.9 inches as of midnight, weather officials said. That makes it Spokane’s ninth snowiest winter already.
Spokane on Monday also broke a daily record for snowfall with 7.5 inches of snow, breaking the previous record of 6.7 inches that fell on Jan. 5, 1959.
The highest snowfall ever for the city was 93.5 inches in the winter of 1949-50, according to the National Weather Service. The winter of 2007-2008 was the second snowiest on record with 92.6 inches.
If the area sees average snowfall for January - 15 inches - and February - 6 inches - then the record should be easily broken, officials said.