As the world warms, the meaning of winter is changing. In the U.S., a greater percentage of winter precipitation is falling as rain, with potentially severe consequences in western states where industries and cities depend on snowpack for water, and across the country wherever there is a winter sports economy. A Climate Central analysis of 65More
It was a rare snow that fell from the skies in two spots at opposite ends of the country early this week: A sprinkling of snow dusted the peak of Hawaii’s Mauna Kea volcano, while nearly seven inches fell atop Mount Washington in New Hampshire.
Snow in the summer sounds bizarre, particularly in the tropical paradise of Hawaii, but given the right combination of unusually cold weather, storms, and high elevations, it can happen.
Many people don’t realize that Hawaii gets any snow at all, Chevy Chevalier, a meteorologist with the National Weather Service office in Honolulu said. But the islands aren’t all sandy beaches and palm trees — they also have volcanic peaks, two of which reach above 13,000 feet.
Those peaks often see snow in the winter months, but “it’s unusual to happen over the summer,” Chevalier said.
The dusting of snow on Mauna Kea (which is Hawaii’s highest point at 13,796 feet), came courtesy of colder than normal temperatures for this time of year as well as thunderstorms that provided moisture.
The last time summer snows fell there was on July 17 of last year, when a bit more than a dusting fell, Chevalier said.
For Mount Washington, which is notorious for its wild weather, the snow came thanks to “a pretty strong area of low pressure that dropped south” from near Hudson Bay in Canada, bringing sub-Arctic air along with it, Tom Padham, a weather observer and meteorologist with the Mount Washington Observatory, said.
That system also brought some fierce winds to the peak; they topped out at 101 mph on Monday. There were snow showers “pretty consistently” during the week, then on Sunday the system dumped 4 inches, Padham said. That was enough for the meteorologists to build some snowmen at the observatory on the peak.
“It was surprising to us,” Padham said, despite his several years working there.
Though the peak has seen measurable snow in every month of the year, conditions like that are rare for June. Typically the month only averages about 1 inch of snow, most of that coming in the first few days. So far this month they have recorded 6.9 inches, making it the third snowiest June on record.
Right now it’s not looking likely that this June will move up in the rankings as the next few days are expected to see a return to more seasonable weather, with temperatures in the upper 40s. In fact, most of the snow that fell has already melted and did so within 24 hours of falling, Padham said.
Saying anything about how such rare summer snows might be affected by the overall warming of the Earth is difficult, as by definition it is hard to find trends for rare events.
But overall, less snow and more rain is expected to fall in the U.S., and in fact already is. In New Hampshire, 80 percent of weather stations are reporting more rain and less snow in the winter months over the last 65 years, according to a Climate Central analysis.