ROANOKE, Va. – There are some parts of the country where extreme weather is more common than other parts.
Hurricanes hit the Gulf Coast and East Coast. Tornadoes happen more often in the Deep South and Plains.
And then there are atmospheric rivers.
Atmospheric rivers can best be characterized as narrow bands of tropical moisture. When these bands move over land, they can become very impactful.
California and the West Coast of the U.S. see them so often, that there’s now a scale devised to show their severity.
One such atmospheric river developed as a slow-moving area of low pressure hit the West Coast this past weekend and earlier this week, dumping feet of snow on parts of the Sierra Nevada.
California’s mountains, like many of the Western mountains, are taller than the Appalachians, Blue Ridge, Smokies, etc.
When air rises up higher terrain, it cools, expands and condenses more efficiently. Therefore, that tropical moisture over higher terrain led to extremely efficient snow rates.
The National Weather Service in Sacramento published storm reports from the most recent storm. Sugar Bowl, California reported 126″ of snow. That’s ten-and-a-half FEET of snow in just four days.
❄️Snowfall Totals Are In! ❄️
— NWS Sacramento (@NWSSacramento) March 4, 2024
Here's a graphic of the 4-day snowfall analysis with the top 4-day totals listed on the left, along with some additional lower elevation locations that measured 2 and 3 day totals. #CAwx pic.twitter.com/YTxEva6upg
UC-Berkeley’s Central Sierra Snow Lab calculated 78″ (6.5 feet) of snow over the four-day period.
Let’s compare that snow with what we’ve seen in recent years, understanding that the Sierra Nevada is a much different and (at times) more extreme climate than ours.
Sugar Bowl’s 126″ of snow over a span of four days is roughly equivalent to what Roanoke has seen in the past decade.
In addition to the intense snow, one weather station at Palisade Ski Resort at Lake Tahoe recorded a wind gust of 190 mph.
There were several other hurricane-force wind gusts recorded during the time of the blizzard in the Sierra Nevada.
Though the weather was extreme, this snow pushes them above the normal amount of snow-water equivalent, meaning that California stands a good chance of avoiding severe drought in the spring.
This could potentially be a sign of a larger shift in a global oceanic pattern.
The El Niño Southern Oscillation appears likely to be moving into a La Niña again in the summer of 2024.
The most recent ocean analysis shows a shrinking area of warmer-than-average ocean water off the coast of Peru.
A La Niña could lead to more frequent storms in the Western U.S. and less storm systems over the Eastern U.S. this coming summer.
The lack of wind shear from Eastern U.S. storm systems, along with record warmth in the North Atlantic, could potentially spell trouble in the 2024 Atlantic hurricane season.