Data coming out of the May 1 snow survey released this week by the California Department of Water Resources reveals some interesting trends. Looking at the big picture, there is clearly significant water content in the high-elevation snow (above 10,000 feet), but how much of that melt will end up in the state’s reservoir system is conjecture.
What is known is that the state’s reservoirs (including Lake Kaweah) are almost full, and that’s highly irregular when snowpack for the entire season measured just slightly more than one quarter of the statewide April 1 average. April 1 (based on the years 1966 to 2015) is used because typically California receives most of its rain and snow before April 1.
But the current season is proving anything but typical. A cursory look at the Kings and Kaweah drainages tells the story for the nearby mountains and national parks. The highest collection station in the Kings River drainage is Black Cap Basin at 10,300 feet. On April 25, when the snowpack was recorded for the May 1 survey, there was 48 inches of snow extant with a water content of 25.0 inches. There was no snow at any of the collection stations below 8,000 feet.
In the Kaweah River drainage, the stats are similar. Farewell Gap at 9,500 feet in Mineral King checked in on April 27 with 32 inches of snow and a water content of 13.5 inches. There was no measurable snow at any station in the Kaweah drainage at an elevation less than 8,600 feet.
How much of that high elevation snow will actually make it down the drainage and end up at reservoirs like Lake Kaweah? According to Phil Deffenbaugh, general manager at Lake Kaweah, there is not sufficient data to predict how much water will enter the basin from the high elevation melt.
But what is certain is that even when rain and snow is substantially below the 50-year average like this year, it is still possible for reservoirs to fill if the majority of that precipitation occurs after March 1. In the state’s larger reservoirs like Lake Shasta (4.5 million acre feet), some of the current lake level (92 percent of capacity, 4.1 million acre feet) is carryover from last year.
So is the rain and snow done for the season? Only time will tell but things are much less dire than they were appearing to be 10 weeks ago.