Rivers From the Sky
A powerful late season Pacific storm descended upon us on Sunday and Monday, dropping some pretty incredible amounts of rain, some places registering double and even triple the entire month’s normal in just the span of 48 hours or so. Here in Laguna as of 1:30 p.m. on Monday, March 21, we’ve collected just over an inch since yesterday. The sun came out right after a thundersquall passed to the north.
This storm focused entirely on California instead of its usual aim at Washington and Oregon. While all the action was going on down here, only a few showers were falling up there. Wind gusts reached 45 mph here late Sunday night. The surf is raging this afternoon with waves coming in several directions and time intervals. There’s a Southern Hemisphere swell at 17 seconds, a south wind swell at 8 seconds, a west wind swell at 8 seconds and a northwest ground swell at 13 seconds making for 4-7 ft. peaks and walls up and down the beach. The water temp. today remains way down there at 54 degrees with no indication of warming any time soon.
Remember that whole #%&@load of rain we got in late December? All the credit for that madness goes to a newly discovered phenomenon called an atmospheric river. Completely unknown until the beginning of this century, these rivers turn out to be a key factor in Western flooding and water supply, but also a major player in the planet’s water cycle.
Like freight trains loaded with water vapor, atmospheric rivers are long narrow bands whose winds funnel huge amounts of moisture through the sky. When they hit coasts, these rivers can drop their moisture as rain and cause destructive flooding as in January of 1969 when Laguna was drenched with nearly 19 inches of rain or in January of 2005 when an atmospheric river deposited over 20 inches in five days on the same terrain, and once again last December when we got up to 25 inches in less than a week. I might note here, this “river in the sky” event has been going on for eons, but it is newly discovered. It’s also known as the Pineapple Express. These bands can be thousands of miles long, but a mere 300 miles wide, but when they focus on one given area, all hell breaks loose!
It looks like we’re about to get hammered by yet another Pacific front with an additional 1 to 2 inches of rain. What La Nina? Until next week, aloha!
Dennis McTighe worked as a meteorologist and NOAA forecaster. He earned an earth sciences degree and has kept daily weather records since 1958.