Kaweah Country dodges threat of rapid snowmelt
March 5, 2019 - 16:47 admin
February 22, 2019
WEATHER WATCH: The forecast for the upcoming week is showing temperatures as much as 20 degrees warmer, both day and night, than were experienced this past week. Lake Kaweah is gradually coming up as is typical for this time of year when the storms are unpredictable. The pool elevation is 614.53 feet above sea level (full is 715 asl); storage is 30,674 acre-feet (full is 185,000 af). Currently, the mean inflow is 860 cfs; outflow is 1,243 cfs.
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Ten days ago, forecasters were saying the potential for a major precipitation event was in the charts. The classic setup for a warm rainstorm on a sizable snowpack could cause a widespread flood in the Kaweah River drainage.
California forecasters were including in every discussion that the split of the polar vortex was making it problematic to predict how much precipitation would fall where. Hanford’s NOAA weather forecasters were broadcasting that Kaweah Country should be prepared for some higher-than-usual flows and flooding in all forks of the Kaweah River.
The river did rise Thursday, Feb. 14, but the peak flow of 5,250 cfs in the Middle Fork wasn’t enough to cause alarm. By the evening of Friday, Feb. 15, temperatures began to plummet and the high elevation moisture began to fall as snow, averting the threat of melting snow coming down the drainages. In fact, snow levels flirted with accumulating down to 2,000 feet throughout the week.
Generals Highway was closed off and on throughout the weekend. At the start of the week, a communications issue caused a closure of the park highway as the recurring storms knocked a tower offline, cutting off the high country from Ash Mountain headquarters, which would create a dangerous situation in the event of an emergency.
All systems were restored and the Generals Highway reopened Tuesday, Feb. 19, at 10 a.m.
On Thursday, Feb. 21, Lodgepole (6,700 feet) checked in with 84 inches of snow on the ground. After starting off sunny, it snowed intermittently throughout the day. Mineral King had about 90 inches at its snow stake at 8,000 feet elevation on Thursday.
The upside of the warm rain on the existing snow was that water pooled on top of the snow pack. When temperatures dropped, an ice layer formed helping to ensure the snow will melt much slower when late-season rains enter the forecast. Now the recurring cold snowstorms ensure that the top layer of the pack is powdery; below is snow that is hard-packed.
In Three Rivers, another two inches of rainfall was recorded in the past week. The season total is now 13 inches (at 1,000 feet) with more accumulation in the up-canyon areas. Temperatures will warm next week and more rain is in the forecast for the first weekend of March.
Some models are showing local temperatures reaching 70 degrees for the first time in 2019 and plenty of moisture during the first 10 days of March.