Know your snow!

10 years ago

Recently, after posting to my professional Facebook page that light snow was occurring over a portion of The County, a couple of people replied, “Light Snow?! It’s really been coming down here!” Then I asked them how much they had had. “Oh, about a half inch”, they said.

So, let’s say it’s snowing where you live and you wonder how fast it’ll pile up if it continues. Turns out that there is a very tidy, easy-to-use rule of thumb for estimating snowfall rates.
Here’s what you do. From a spot on your property where you can see at least one mile, mark off a quarter mile, a half mile and one mile.
If it is snowing, and you can see at least one mile, if not more, you are receiving light snow, and hourly accumulation rates will be less than one inch. If, on the other hand, your visibility is limited to your 1/2-mile marker, you are receiving moderate snow, and this generally accumulates at a rate of one inch per hour. Now if it is really coming down, and your visibility is restricted, such that you cannot see beyond your 1/4-mile marker, you are receiving heavy snow and it will accumulate at least 2 inches every hour.
These are the official dividing lines, as one would report them to me at WAGM:
Visibility at least 1 mile? Report “Light Snow.”
Visibility 1/2 mile? Report “Moderate Snow.”
Visibility only 1/4 mile? Report “Heavy Snow.”
So now, in the midst of a snowstorm, you can estimate the rate at which it is accumulating by using only visual markers at the distances described. Kinda cool!
On a completely unrelated note, northern Maine saw a rather unusual temperature occurrence on November 24th. Following showers in advance of a warm front, the warm front itself moved through, and temperatures steadily rose, right into the evening hours, reaching 56 degrees at NWS Caribou at 10 p.m.. This broke the record high for the date of 55 degrees, set back in 1967.
To have broken a high temperature record in late November during the nighttime hours in a month that has otherwise been cold, is interesting indeed!
  Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been Chief Meteorologist at WAGM-TV since 2006. Email him at