A series of back-to-back atmospheric rivers will bring severe gusts and up to 10 inches of rain to parts of the West Coast – with incessant storms expected through Wednesday.
More than half a dozen states are under a winter warning as the atmospheric river brings up to a foot of snow and rain to Idaho, Wyoming, Colorado, northwest California and Utah.
The heaviest rainfall is expected to occur in western Washington state.
Another atmospheric river will add to the 40 inches of snow that has already blanketed the area’s mountains – and in Wyoming, winds of up to 60 miles per hour are expected in some areas.
A series of successive atmospheric rivers will bring severe gusts and up to 10 inches of rain to parts of the West Coast
More than half a dozen states are under a winter warning as the atmospheric river brings up to 12 inches of snow and rain to Idaho, Wyoming, Colorado, northwest California and Utah
The predicted flooding is due to a weather phenomenon known as atmospheric river, a band of water vapor that can extend 1,000 miles long and 350 miles wide.
As moisture moves inland from the tropics to higher latitudes, extreme snow and rain can occur, as well as the possibility of flooding.
The National Weather Service office in Portland, Oregon, warned: “Flooding from excessive rainfall is possible for all locations west of the Cascades through next week.”
“Those living in flood-prone areas should be prepared to take action in the event of flooding.” Monitor the latest forecast and be aware of possible flood warnings.
Meanwhile, areas near Seattle have been warned that avalanches could occur if the storm continues.
These include Stevens and Snoqualmie passes, the western slopes of the southern Washington Cascades and Mt. Hood.
The National Weather Service Prediction Center said, “This will allow milder air to move into western Oregon and Washington, making rain the predominant type of precipitation.”
It has already snowed in parts of Washington, turning the landscape into a winter wonderland
“The Winter Storm Severity Index (WSSI) indicates that severe impacts are possible in the highest elevations of the Pacific Northwest and the Rocky Mountains, which will likely result in dangerous or even impossible travel conditions in these affected areas.”
“With heavier rainfall over the weekend, soils will become more vulnerable and therefore there is a risk of major runoff and flooding.”
“Snowfall amounts are expected to be fairly high initially, so there may be additional flooding risk on the west-facing slopes of the Cascades due to snowmelt.”
Chad Hecht, a meteorologist at the Center for Western Weather and Water Extremes at UC San Diego, told CNN: “In scenarios where we see multiple atmospheric rivers moving on land in the shape of a family, the hydrological impacts due to the “It is time for rivers and soils to return to baseline levels.”
In early November, the first snowfalls of the season blanketed the Rocky Mountains, the Great Lakes, and New England, resulting in the most extensive early November snowpack in at least two decades.
Meanwhile, areas near Seattle have been warned that avalanches could occur if the storm continues
According to the National Oceanic and Atmospheric Administration, 17.9 percent of the contiguous United States had snow on the ground.
At about the same time last year, only 3.4 percent of the area was covered in snow. The 20-year average snowpack across the Lower 48 is 5.5 percent as of November 1st.
“There have been 2,700 local storm reports with ice or snow in the last week,” AccuWeather meteorologist and social media producer Jesse Ferrell said Wednesday.
Trick-or-treaters from Minnesota to New York saw snow on Halloween, and there was enough snow to shovel in cities like Minneapolis, where it was between 2 and 4 inches.