On Saturday, February 25th, the citizens of Claremont woke up to something unprecedented: snow blanketing the roofs, backyards, and trees of Claremont. Bewildered and delighted, citizens enjoyed the rare sight. As enjoyable as the sight of snow was, however, this was no winter miracle. Instead, it is an ominous warning of the effects of climate change.
The reason that snow unexpectedly fell upon Claremont in a way that it has not in decades is due to atmospheric rivers, which are “long, narrow highways of moisture”, according to the National Oceanic and Atmospheric Administration (NOAA). These atmospheric rivers lie around 10,000 to 15,000 feet above the surface of the Earth, traveling thousands of miles across the planet while being responsible for 30-50% of the wet season precipitation along the West Coast of the U.S., according to NOAA. A strong atmospheric river can transport an amount of water vapor that is “roughly equivalent to 7.5–15 times the average flow of liquid water at the mouth of the Mississippi River,” NOAA has found.
However, this winter, California has been hit with multiple atmospheric river events. According to analyses, the atmospheric rivers carrying warmer water have shifted to cross over more of California than usual. In fact, in the past three months alone California has experienced twelve atmospheric rivers. This has caused winter storms to deposit over 100 inches in the Sierra Nevada mountains, causing a trickle-down effect in which over a foot of rain has hit areas of California, an unprecedented amount. Historically, the path of the atmospheric rivers merely skims California, diverting most moisture away from the state. This is why California’s climate has always been dry, and why the sudden influx of water has been shocking to its citizens and scientists.
The reason for these atmospheric rivers shifting is because of climate change. As temperatures increase across the globe, so do moisture levels in the atmosphere. In turn, atmospheric rivers can hold more moisture, causing an even greater increase in rainfall across the state. Although this has helped ease the state’s record drought, it has also caused catastrophic flooding, displacing hundreds of people and destroying thousands of dollars in property.
Although the rare snowfall Claremont has experienced over the past few weeks has seemed to be a blessing, it is truly a warning in disguise, a warning that must be heeded. As the past month has shown, climate change is not a faraway, distant threat. It affects the people of Claremont even today, and its effects can be seen as close as their backyards.
