Tuesday, April 28, 2015

Pacific Northwest’s ‘Wet Drought’ Possible Sign of Future

Unusually low snow levels seen at Oregon's Crater Lake on April 21, 2015. (Credit: NPS) Click to Enlarge.
The drought in California is one of both heat and dryness, as a persistent ridge of high pressure that parked itself over the western U.S. over the past two winters blocked much-needed storms and drove up temperatures to spring and summer levels.

Oregon and Washington, on the other hand, are stuck in a seemingly oxymoronic wet drought.  The storms that were prevented from hitting California did provide rains to the Pacific Northwest, with winter precipitation in Oregon only about 30 percent below average, not even in the bottom 10 years historically, said Philip Mote, director of the Oregon Climate Service.

But the sky-high temperatures that marked the warmest winter on record for Washington and the second warmest for Oregon meant that much of the precipitation fell as rain, and not snow. Like California, parts of both these states depend on melting snowfall to fill their reservoirs, leaving them with potential shortages this year.  Elevated temperatures also meant that what snow there was melted much earlier than normal.

Three-fourths of snow survey sites in Oregon had record-low snow measurements as of April 1, and fewer than half of them had any snow on the ground, according to a report by the Natural Resources Conservation Service.  The snowpack across much of the Cascades Range in Washington was less than 25 percent, while the Olympic Mountains checked in at only 3 percent on April 1, an “unbelievably low”  amount, Karin Bumbaco, assistant state climatologist in Washington, said.

Water and Wildfires
Those numbers, along with expectations that the drought conditions will persist if not intensify, have officials bracing for impacts this spring and summer.

“The two themes that keep coming up are summertime water supply and wildfires,” Dello said.

The water shortage concerns aren’t as widespread as in California because the western parts of Oregon and Washington tend to depend solely on rain, and so their supplies are fairly healthy.  But in eastern areas that do depend on the snowpack to keep reservoirs topped up, residents and officials “are really concerned about what’s going to happen,” Dello said.

Read more at Pacific Northwest’s ‘Wet Drought’ Possible Sign of Future

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