Storms from the Pacific Ocean normally bring rain and snow to California during the wet season. But for the past two years, an area of extreme atmospheric pressure has blocked the way. Noah Diffenbaugh, an Associate Professor at Stanford University, says his team calls it the “Triple R.”

PhotoDIFFENBAUGH: “The ‘Triple R’ stands for the ridiculously resilient ridge.”

Diffenbaugh says you can compare the dynamics of the Triple R to what happens when a large boulder lands in a small stream…

DIFFENBAUGH: “The water will move around the boulder.”

Similarly, storms heading for California were deflected north to Canada and Alaska by the ridge. Diffenbaugh says ridging in the atmosphere is common, and has been associated with dry seasons in the past.

DIFFENBAUGH: “What really is different about the conditions during this current drought has been the resilience of these conditions.”

Researchers have never seen an atmospheric event that rivals the persistence and intensity of California’s Triple R and they’re not sure why it’s been so strong.

However, Triple R events may become more frequent in the future. Diffenbaugh’s team found that they are three times more likely to occur today than in pre-industrial times.

Reporting credit: ChavoBart Digital Media.
Photo: Copyright protected.

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