Snowiest season finally ending
I think we have seen the end of the accumulating snows for the season.
Normally, by the first week of April, that kind of forecast would pretty much be a no brainer. After the kind of early spring weather the area has seen, however, I find it hard to issue any sure bets against Mother Nature.
During an average March, Spokane usually sees about 3.5 inches of snow. This March ended with nearly 16 inches. April’s average snow is a sparse half an inch. Fortunately, even if a significant dose of snow – several inches – were to fall this time of year, the longer daylight hours and higher sun angle would melt whatever stuck to the ground pretty quickly.
Coeur d’Alene usually sees somewhat higher amounts of snow. The average is nearly 6 inches for the month of March, and nearly an inch for the month of April. Crazy March 2008 brought nearly 32 inches of snow to Coeur d’Alene as measured by local climatologist Cliff Harris.
While Coeur d’Alene has seen the snowiest winter on record (nearly 168 inches), this winter season now ranks third snowiest for Spokane with 87.8 inches.
The Northwest has not been alone in seeing record snowfall throughout the season. Several locations in the Great Lakes region have seen record or near record snowfall this winter, including Madison and Green Bay, Wis., and Flint and Grand Rapids, Mich. Record snowstorms also affected cities in Missouri and Arkansas, which later had to deal with severe flooding when melting snow combined with heavy rains.
Flooding is also a concern in the spring across the Inland Northwest. Warm temperatures which can rapidly melt mountain snowpack, along with heavy rains, can lead to rapid rises in local rivers and streams. A flash flood is a type of flood that occurs in a short amount of time. Within a few hours heavy rains, ice jams, and/or melting snow can turn even small streams into raging torrents. Dam or levee failures can also result in flash flooding. Flash floods can occur with little warning and can even affect urban areas where paved areas leave little room for rainfall to be absorbed into the ground.
Nationally, floods kill more people each year than any other type of weather phenomenon. Nearly half of all flash flood related fatalities are auto related. One simple rule to remember if you encounter water across the roadway, “Turn around, don’t drown!”
In an average year, there are 27 flash flood events across the states of Washington, Idaho and Oregon. In contrast to flash flooding, river flooding occurs over a period of several days. River crest forecasts sent out by local weather service offices can help people prepare for rising waters.
Answers to questions
When asked what brought on such a snowy winter, it would be easy to point to La Niña.
La Niña winters are notorious for being wetter and colder than normal across the Northwest. The atmosphere is more complex than that, however, and you can’t always single out one factor as causing a particular seasonal weather pattern. There have been extremely snowy seasons without the presence of La Niña, and there have even been snowy winters when the opposite phenomenon, El Niño, was occurring.
I also recently received an e-mail inquiring about whether an extremely cold and snowy winter would lead to a milder summer, as has happened a few times in past history. There have been no studies that have shown such a correlation. That said, La Niña conditions are forecast to continue through the spring, which would point toward a cooler and wetter weather pattern for this region into June. As far as summer 2008….we’ll have to wait and see.