A weather phenomenon called an atmospheric river aka Pineapple Express is set to send soaking rains and mountain snows to the state of California this week. While the moisture coming from the skies may seem like a God-send to this drought-stricken state, the flooding, rock/mudslides and even damaging winds will not be welcomed by most state residents. The National Weather Service stated earlier this week that this upcoming storm may be one of the most powerful storms to hit California since October 2009.
The Pineapple Express gets it name due to the origin of the moist plume in the central Pacific near the Hawaiian islands. This atmospheric river is making its way down the western coast of the United States this week, dumping heavy rain from the western portion of Washington into northern California. On Tuesday, the first round of heavy rainfall soaked portions of western Washington with the bulk of the heaviest rain expected to fall on California’s west coast during the daytime hours Wednesday. From Wednesday night into Thursday, the storm system will slowly move through northern and central California as the southern portion of the strong Pacific jet stream pushes its way into the region. There is a real threat of flash flooding in many areas along the state’s western shoreline and further inland and especially in low-lying areas.
The National Weather Service 3said that anywhere from 3 to 5 inches of rain will fall in western Washington and the San Francisco Bay Area this week. Up to 8 inches of rain could come down along the Sierra foothills that are located below snow level as well as along coastal ranges and some locations in the Olympic Mountains. Flash floods, mud and rockslides are very possible in these areas as are debris flows because the ground is saturated from last week’s heavy rain. There are winter storm watches in effect for portions of the Sierras where up to 3 feet can come down between Wednesday afternoon and Friday. Travel in those areas will be hazardous as roadways will be be snow covered and slippery with visibility affected by winds that could gust in excess of 60 miles per hour. High wind watches are also in effect for many areas including the metropolitan San Francisco area.
Late Tuesday, the NWS issued a blizzard warning for northern California communities above 6,000 feet including Lassen National Park, Donner Pass, Echo Summit and Carson Pass. The warning will remain in effect until 1 pm Friday. The weather service is warning people in those communities to expect white-out conditions which could lead to roadway closures that last several hours