After years of drought, parts of California have experienced near-record precipitation in 2017. In the mountains, that means snow—and the Sierra Nevada has had so much snow this year that some ski resorts are planning to stay open until August. In addition, the cool spring delayed the onset of snowmelt, meaning that rivers are higher and wilder than normal for this time of year, and rather than dealing with drought, Californians are dealing with an increased risk of flooding.
What to Expect
River flows will be much higher than normal—for more of the year. This year’s snowmelt has created unusually hazardous conditions in California’s surface waters. Over Memorial Day weekend this year, 3 people died in the Kern River, and 99 more were rescued from the Kern and other California rivers. A whitewater river in full spate is dangerous under any conditions—and “full spate” in 2017 has been well above normal. Along the South Fork of the American River, for example, normal summer flows are around 1,750 cubic feet per second (cfs); by May 27 of this year, the South Fork was flowing at 6,000 cfs. Flows of 3,000 to 6,000 cfs are expected to continue into July—something that hasn’t happened since 2006. Another California river, the Tuolumne, was up to more than five times its normal flow in early May, carrying more than 10,000 cfs, and it’s expected to continue at that high flow until after July 4. In some places, much higher than normal runoff levels may continue late into August. This means hazardous conditions on the river, around the river, and downstream from the river.
Flooding could be an issue. All that excess water in rivers and in reservoirs creates excess flood hazards. California’s reservoirs have been filled to overflowing this year—and that has caused flooding and flood warnings in many areas, as well as concerns about the stability of California’s dams. Most recently, the Kings River breached a levee in Grangeville, and flood advisories were issued for both the Kings River and the San Joaquin River.
Here’s how you can prepare to monitor and respond to the new, wet-weather patterns and hazards.
- Keep an eye on conditions. The California Nevada River Forecast Center (CNRFC) can provide you with up-to-date information on the flood potential in your area. You’ll also want to pay attention to conditions at nearby reservoirs, where strained infrastructure may be as much of a problem as water levels themselves.
- Be prepared to act quickly. If your area is facing flood potential, you can contact your local fire department for information about sandbags.
- Update your emergency action plan. If flooding could affect your workplace, make sure that your employees are up to date on applicable emergency procedures.