I was watching Governor Brown of California the other day as he held a press conference about the unprecedented drought striking California. Part of my brain was thinking, how could I possible garden in those conditions, then the less ego-centric side kicked in and began thinking about the hardships placed on the residents of that state and how long the drought could last.
Past Snow Droughts
Pictures from the Sierra Nevada this week cv reminded me of Lake Placid back in 1980. That year, before the Olympics began, the lack of snow was augmented by snowmaking being used for the first time. Head into the way back machine to the same venue in 1932. Then, the lack of snow forced planners to truck snow in from across the international border.
Charting New Records
It’s amazing to see how little snow has fallen in that part of the country this season. By most estimates the amount of water locked up in the snow is only 6% of average. This shatters the other previous records of last winter and the winter of 1976-77 when about 25% of average snow fell in that region. Think about this, last year there was 4 times the amount of snow on the ground as compared to this week and those 2013-14 numbers were very low.
If we had seen 6% of average snow here for a winter there would be about 2-8 inches of snow the entire winter across most of New England. By some measures that was the winter of 2011-12.
The heat and dry conditions out west are related to the cold and snow here in the northeast. When the jet stream gets stuck in any one position areas will experience the same basic type of weather for weeks, months or even years. Although the flow of air has temporarily shifted during the past 12 months, there has been a persistent ridge in the west and trough in the east since last winter.
Weather is about balancing the atmosphere, and when you have an extreme on one end of the jet stream, you end up with another extreme further down the flow. Notice while we had our coldest January through March period, the west was seeing record warmth.
Early Winter Hope
In December, when it was quite wet and mild, the pattern also brought more typical precipitation to California. This was a hopeful sign the winter precipitation would be closer to average out there. However, in January, when the new pattern became locked, snow and cold resulted here while dry and warm weather occurred there.
Interestingly another low snow year for the west, 1976-77 was a very cold and snowy year here in the east.
The Big Variable
Much of this is likely related to the Pacific Decadal Oscillation, an internal switch between slightly different circulation patterns of the waters off the coast of the North Pacific Ocean. This shift can warm and cool the land masses of North American and contribute to a change in the flow of the jet stream. You can see in the image below how the PDO changes roughly every 30 years.
This phenomenon has been studied for about the past 20 years and I suspect there is much more we can learn about its relationship to our weather and indeed even climatic shifts. While we continue to try to predict what future weather might bring to various regions of the country, both the public and private sector are going to need to plan for weather events that aren’t in the record books, as new records will continue to be established.
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We shouldn’t think somehow everything officially measured from the late 1800’s until today will remain. Being prepared for what’s already occurred and using those as benchmarks won’t be enough. Extremes of weather will continue to set new records and challenge how we adapt to them.