Flooding, mudslides to threaten Northern California into Tuesday
By Renee Duff, AccuWeather meteorologist
February 19, 2017, 3:13:27 PM EST
Heavy rain and mountain snow will pound the northwestern United States early this week, with the most significant impacts targeting Northern California.
Storms will resume their track across the region following a brief break from heavy precipitation to start the weekend.
Precipitation will become more widespread and heavy throughout Monday, with the heaviest rain expected to slam Northern California.
A widespread 3 to 6 inches of rain can fall across the San Francisco Bay region and part of the Sacramento Valley through Tuesday, with locally higher amounts possible across the foothills.
“While the storms will bring the risk of mudslides and avalanches, the greatest threat to lives and property will be from flooding,” AccuWeather Senior Meteorologist Alex Sosnowski said.
Significant rainfall so far this winter has left reservoirs full and many rivers near or above flood stage. Additional rainfall will struggle to seep into the saturated ground causing excessive runoff.
Residents who live near streams and rivers as well as downstream of reservoirs should monitor the weather closely over the next few days.
Evacuations may be ordered in some communities if the threat for flooding is imminent. This includes near Oroville Dam, where crews have been repairing a damaged emergency spillway that sparked fears of a major flooding disaster last weekend.
California Department of Water Resources officials are confident Lake Oroville will be able to withstand the rainfall early this week, according to The Sacramento Bee.
Motorists should be on alert for pooling of water on roadways and perhaps closed roads.
Significantly less rainfall will reach Portland, Oregon, to Seattle where the threat for flooding will be very isolated. Still, rain and a low cloud ceiling can make for disruptions to travel on the road and in the air.
Unlike the deadly rainstorm that caused significant flooding to end the past week, this storm will stop short of spreading heavy rainfall into Southern California. At most, spotty rain and drizzle will affect the Los Angeles Basin early this week.
Feet of snow will further bury the Sierra, including I-80’s Donner Pass. While the snow will not be quite as heavy across the Cascades, slippery travel will still pose problems.
“Episodes of snow and an icy mix will also lead to travel hazards over the interior Northwest, east of the Cascades,” Sosnowski said.
Gusty winds will accompany the rain and snow and heighten the risk for fallen trees, downed power lines and sporadic power outages.
While no major storms are expected to follow the early week deluge, several weaker storms will unload additional bouts of rain and snow across the West Coast into next week.
The wet weather from these storms will tend to be spottier and less intense.