December 31, 1996 in Nation/World

Warm-Up Brings Fear Of Flooding Heavy Rain Expected With Temperatures In The 40s

By The Spokesman-Review
 

After piling up the most December snow on record, the Inland Northwest is about to see some of it disappear.

Old-timers talk about a January thaw as typical of winter in the region. This year’s melt starts a day early.

On Monday, the National Weather Service issued an urban and small stream flood advisory for northeastern Washington, North Idaho and southeastern Washington.

A near seamless series of potent Pacific storms is expected to scour any remaining cold from the valleys of the Inland Northwest today.

Rain, heavy at times, is forecast to fall throughout the region, and temperatures are expected to rise into the 40s and stay there through Wednesday.

“The heavy rains, the significant rains are coming in Tuesday night,” said Paul Frisbie, forecaster for the National Weather Service.

As much as 0.75 inch of rain is expected in Spokane with upwards of 2 inches in parts of the Idaho Panhandle.

Because of the thawing temperatures, the threat to snow-laden residential structures should ease, Frisbie said. Any rain should be balanced out by thawing and draining from peaked roofs.

However, flat roofs that are not draining properly could be in danger of collapsing from the weight, Frisbie said.

December is going down as the snowiest ever since snowfall records have been tabulated, starting in 1885.

A total of 42.7 inches of snow fell in December, just eclipsing the 42 inches that fell in 1964 and the 40.2 inches that fell four years ago.

The average for December is just below 15 inches.

The highest one-month snow totals ever in Spokane came in January 1950 with 56.9 inches and January 1969 with 48.7 inches. Those years are widely regarded as the two worst winters in modern times.

Not only did December set a snowfall record this year, but it also contributed to a record for the highest amount of precipitation for the three months ending today.

So far, 10.59 inches of rain and melted snow have been measured in Spokane since Oct. 1 with more on the way today. The old record was 10.58 inches in 1955.

Much of the recent precipitation is sealed in the snowpack around the region, so forecasters are concerned that a fast meltdown with heavy rain could trigger severe flooding.

However, the current warm-up is expected to end by this weekend when daytime temperatures fall back into the low 30s, which is close to normal for this time of year.

Computer forecast models show the storm track shifting southward by the weekend, leaving the Inland Northwest with a chance of lighter snowfall amounts.

The current flood threat should be confined to urban areas where the snow melt would be the greatest, and small streams, which drain low lying areas.

Flooding could be more severe in areas of southeast Washington where higher temperatures are expected for a longer period of time.

Frisbie said larger river systems in northeast Washington and North Idaho probably will be spared from flooding for now because rain, which is expected in the mountains, will be absorbed by the deep snow.

“The snowpack will soak up a lot of rain,” he said.

Any short-term warm-up could ease the threat of serious flooding next spring by releasing some of the water that’s been held in the snow, Frisbie said.

In lower elevations, roads that have not been plowed could become impassable as the snow turns to mush today and Wednesday, he said. , DataTimes ILLUSTRATION: 2 Color Photos

MEMO: These 2 sidebars appeared with the story: 1. (This sidebar appeared in Spokane edition only.) PASSES CLOSE The Washington Department of Transportation has shut down all the state’s passes until at least Wednesday due to adverse weather and road conditions. Snow, rain and ice were responsible for accidents throughout the state, especially in the mountains, according to the Washington State Patrol. State Highway 20 from Sherman Pass east of Republic to the Stevens County border was shut, and the WSP said it is not known when it will reopen.

2. (This sidebar appeared in Idaho edition only.) PASSES The Washington Department of Transportation shut down all mountain passes until at least Wednesday due to adverse weather and road conditions. State Route 20 from Sherman Pass east of Republic to the Stevens County border was shut down, and the WSP said it is not known when that stretch of road will reopen. Idaho passes are open.

These 2 sidebars appeared with the story: 1. (This sidebar appeared in Spokane edition only.) PASSES CLOSE The Washington Department of Transportation has shut down all the state’s passes until at least Wednesday due to adverse weather and road conditions. Snow, rain and ice were responsible for accidents throughout the state, especially in the mountains, according to the Washington State Patrol. State Highway 20 from Sherman Pass east of Republic to the Stevens County border was shut, and the WSP said it is not known when it will reopen.

2. (This sidebar appeared in Idaho edition only.) PASSES The Washington Department of Transportation shut down all mountain passes until at least Wednesday due to adverse weather and road conditions. State Route 20 from Sherman Pass east of Republic to the Stevens County border was shut down, and the WSP said it is not known when that stretch of road will reopen. Idaho passes are open.


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