Sometimes seasons get out of whack. Just as Indian Summer can come on strong and late, winter can show up early. With the change of the leaves, the clocks, and the calendar, there is more interest in snow these days. But how about a White Halloween? It has happened, with much more than frost on the pumpkin. But it is rare. This map shows the odds of snow of at least 1 inch on the ground or measurable snow falling on October 31.
We only have to go back to 2011 for one of those rare storms here in the Mid Atlantic, but the odds must be calculated going much farther back. That is what Brian Brettschneider, a PhD Climatologist did. This is the same man who brought us the year long trip of 70F weather. Here he shows us the odds of a White Halloween. Truth be known, he is from Alaska. See their map below.
Halloween Snow: October 2011 storm
The October 29 to 30, 2011 storm brought snow to metro Baltimore, but was challenged in the city and south by the warming influence of the Chesapeake Bay. This event only ranked a Category 1 on the North East Snowfall Impact Scale (NESIS), but was crippling in parts of Maryland, Pennsylvania and New England. With leaves still on the trees, the northern Baltimore suburbs received an average of 3 to 6 inches of snow near and north of the Mason Dixon line (Baltimore’s BWI only recored 0.1″). There were spots in southern Pennsylvania that came close to 10 inches and snow was still rather deep on the ground for Halloween just a few days later.
I know, I was in it. We had 5 inches of snow at my house and lost power for 5 days. Nothing fun about that. While it was an interesting experience, the kids has trouble making it to the front steps of some houses trick or treating. One neighbor had melt/refreeze ice on her steep driveway and slid the candy down to the sidewalk for the kids. I don’t know when we might see that again. Faith in the trick-or-trick Flakes*?
Deep snowpack can refrigerate the warmer ground and inhibit the sun melting. Consider that the sun angle in late October is more than 5 weeks after the autumnal equinox. That is equal to the solar angle and intensity of the sun in the second week of February.
To have snow on the ground from prior events is difficult with warmer ground to melt snow quickly. The average high is still 63F
A Closer Look
October Snow (With Baltimore as the center point of the Mid Atlantic for reference)
In 132 years of records:
October Snow= 16 times
Oct 30 in 1925 = 2.5″
Oct 19-20 in 1940 = 1.3″
Oct 10 in 1979 = 0.3″ *Orioles World Series
October 31 snow = 0
Back to our friend from Alaska. Brian Brettschneider just tweeted that Anchorage just got snow, avoiding a snowless Halloween this year.
His closer view map on that fine state shows their odds are much greater than ours. You should also consider that despite how dark it might seem at 5 PM here next week, they only have a few hours of daylight for their trick or treaters.
Odds Of A White Alaskan Halloween
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