Winter weather may offer precipitation boost today
With a winter weather advisory issued for Thursday morning, there’s a chance the precipitation levels in the Sierra will get their first real boost of 2020.
The National Weather Service has issued an advisory for 4-10 a.m. Thursday. While snow accumulations are expected to be light in Carson Valley, there is a possibility of slick roads across Western Nevada and Lake Tahoe.
As of Monday, the snowpack on the northern side of Lake Tahoe is right in line with measurements taken just a few days ago on the south side.
The Natural Resources Conservation Service conducted its first snowpack survey of 2020 on Monday at the Mt. Rose Ski Tahoe snow telemetry site.
Data collected by Service Hydrologist Jeff Anderson showed a snow depth of 54 inches, 16-inch water content and the snowpack to be 107 percent of median. This time last year snow depth was 36 inches and water content was 8.9 inches.
While the snowpack is average for the date, precipitation is below average at 72 percent of median.
The snowpack reading on Jan. 2, at Phillips Station near Sierra-at-Tahoe, was 97 percent of normal.
“We need an above average winter to have an average precipitation year,” Anderson said.
October and most of November was dry, so the soil remained dry, even after snow started falling. That means, in the spring when the snow begins to melt, the soil will absorb the snowmelt which will lead to a below average run-off.
As far as precipitation goes, Anderson isn’t worried yet.
“It’s not like we can’t make it up,” Anderson said. “There is still a lot of winter left.”
Truckee and Carson River Water Master Chad Blanchard isn’t panicking yet either. He said, the water reserves are in a good place.
“Tahoe has a foot and a half to go until it’s full, we don’t want to completely fill it up this early,” Blanchard said.
He also echoed Anderson’s sentiment that there is still a lot of winter left to go but even if we don’t make up the precipitation, Blanchard said there is enough water for the summer.
“If we can fill Tahoe, we have water supply for three years,” Blanchard said.
Still, rain and snow can’t hurt. If the summer is hot and dry, a lot of reserved water will be lost due to evaporation.
“We need precipitation and run-off to offset evaporation,” Blanchard said.
SNOTEL sites at 85 locations collect snow and precipitation data all year round. A snow-pillow is a scale that measures the weight of the snow and a tube at the site measures precipitation amounts.
While the site collects data every hour, Anderson double checks data coming from the site at the beginning of January, February, March and April.
Anderson puts a hollow tube into the snow all the way down to the soil. The tube has measurements on the side that tell him the depth. He then weighs the tube with and without the snow and subtracts the tube weight from the snow weight. He does this multiple times around the site.
The large tube that measures precipitation has a white line toward the top that marks where the snowpack was in 2017, a historic snow year. There is a lot of empty space between that line and this years snowpack.
“There’s no record snow depth today,” Anderson said.