Alaska just reported one of the most extreme snowfall rates on record: 10 inches per hour

By John Hopewell
7 December 2017
(The Washington Post) – Imagine going into a movie theater to check out the latest science fiction flick and there is not a single flake of snow on the ground. A couple hours later, as the credits start to roll, you mosey outside and are stunned to find your car buried in more than a foot of snow.
Perhaps you’d wonder if you were still watching a movie.
Well that’s kind of what happened Wednesday at Alaska’s Thompson Pass, just outside of the town of Valdez, when an incredible 10 inches of snow piled up in one hour — around 1.7 inches every 10 minutes. This is an absolutely incredible snowfall rate.
The furious storm dropped another 5 inches in 30 minutes, for a remarkable 15 inches in a brief hour and a half period. In the end, 40 inches of heavy wet snow accumulated in 12 hours.
The Thompson Pass storm ranks among the most intense snowfalls that we know of, according to a quick analysis by Weather Underground’s weather historian, Christopher Burt.
Burt told us that on Dec. 2, 1966, 12 inches fell in 60 minutes in Copenhagen, N.Y., and on Jan. 26, 1972, Oswego, N.Y., was inundated with 17.5 inches in a two hour period. Not surprisingly, both of these records were the result of the snow machine blowing off Lake Ontario.
The Alaska storm was definitely not lake-effect, but a similar amount of moisture was involved. An atmospheric river — a plume of very wet air — transported warm, Pacific Ocean moisture all the way up into the high latitudes and smacked into the mountainous coast of Alaska. [more]

Alaska just reported one of the most extreme snowfall rates on record: 10 inches per hour