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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Warm weather leads to widespread flooding

Michelle Boss Correspondent

It’s another case of weather extremes from one side of the country to the other.

Here in the Inland Northwest, five days of very warm weather last week rapidly melted snow across area mountains, leading to widespread flooding. This occurred even with the below-normal precipitation we have seen so far this month. Previous months featured near-average precipitation, but colder-than-normal temperatures. The result was above-normal snowpack which had only experienced gradual melting until recently.

A large ridge of high pressure encompassing the entire western U.S. was responsible for the summerlike weather last weekend. Although high temperature records weren’t broken locally, records were smashed and/or triple-digit heat was recorded in locations across Western Oregon and Washington, Southern Idaho, Northern and Southern California, and Nevada.

Just as temperatures finally cooled down, heavy rains up to nearly an inch in some spots added to the excess of water in the region. The Spokane River in Spokane saw minor flooding in the Peaceful Valley area, along Harbor Island, as well as along Upriver Drive and the Riverpoint industrial area. In North Idaho, minor flooding was reported at Lake Coeur d’Alene, the Coeur d’Alene River at Cataldo, as well as the Moyie River at Eastport and the St. Joe River at St. Maries.

During these recent floods, the National Weather Service issued flood warnings and flood advisories. The difference between the two might have been confusing. Flood warnings are issued when rivers are expected to rise above flood stage and become a threat to life and/or property. Flood advisories are issued when river or stream flows are elevated but not expected to rise above flood stage. Advisories can also be issued when significant ponding of water is occurring or forecast to occur. The lead time for such issuances is usually within 24 hours. Flood watches can also be issued when forecasters see the potential for weather conditions that could lead to flooding. A flood watch can be issued as much as 48 hours in advance of the forecasted event.

The local National Weather Service office receives river stage information from the regional River Forecast Center in Portland. The Portland RFC is one of 13 across the U.S. and covers parts of seven states, including Washington, Oregon, Idaho and Montana. These offices specialize in flood and water resource forecasting, river modeling and hydrologic system development. During periods of non-flooding, the RFCs make daily streamflow forecasts for water management agencies and prepare seasonal water supply forecasts.

While folks here have been dealing with problems due to the high water levels, weeks of rain have been welcome across the drought-stricken southeastern United States. Atlanta has received nearly 2 1/2 inches of rain in the last two weeks, but it will take much more than that to solve the area’s water shortage. Infamous Lake Lanier, the chief source of water for the 5 million people in the Atlanta metropolitan area, is still 13.2 feet below normal, which is only inches away from the lowest levels on record for this time of year. Add to those woes wildfires in Florida, which have burned more than 75,000 acres already this season, and have resulted in unhealthy air quality in some parts of the state.

Though more seasonable, warmer temperatures should arrive by Memorial Day, summerlike weather will be kept at bay through the end of the month. Normal highs this time of year are in the upper 60s to near 70 degrees.