Why Snow Causes More Tree Damage in Fall Than Winter

A surprise October snow takes out an astonishing amount of trees.

On October 29, 2011, the Mid-Atlantic and Northeast U.S. were racked by a Halloween snowstorm that no one took seriously until they woke up to blizzard conditions on Saturday. Tree damage from the snow was astonishing – from Pennsylvania to Maine, tree limbs crashed on power lines, taking out massive portions of local power grids. When the snow ended, every neighborhood in the storm’s track had lost trees and nearly 3 million households were without electricity.

 Pictures of the surprise October Snowstorm 
October snow storm Pennsylvania tree damage

View from my window as the storm began. Click for larger image

Northeast Pennsylvania never saw significant snowfall in October – in fact this storm was our heaviest October snowfall EVER – seven inches. The amount of snow wasn’t more than a typical winter storm – from 1 inch in the suburbs of Philadelphia to 26 inches in Massachusetts. But the damage to trees was devastating – more extreme than even Hurricane Irene in September. Only three inches of snow fell in New York City’s Central Park, but nearly one thousand trees were damaged or destroyed.

What made this snowstorm so much more destructive to trees?

Leaves and warm temperatures. When snow falls in winter, much of it safely passes through a deciduous tree. The tree has dropped its leaves because it’s entered a winter dormancy period, which starts in late autumn. For the most part, a tree rides out the entire winter, storm after storm, intact.

fall snow storm Pennsylvania

Raspberry canes pinned down by snow

When a snowstorm arrives in October with temperatures hovering around 32 degrees, as this storm did, the snow is heavy and wet. Most deciduous trees had only begun to drop their leaves. The snow clung to the leaves, limbs and branches at the top of the trees which then acted like a sailboat’s sail, catching the wind, adding thousands of pounds of strain. The weight of the snow forced limbs to bow towards the ground, exposing more branch area and more leaves, which in turn collected more snow, adding more weight. Entire trees snapped under the strain. Just after the storm I saw a tree which looked like it had exploded – the tree was split in half as if a giant had chopped the tree with an axe straight down the vertical center. All that remained was a three-foot jagged stump with the limbs, upper trunk and branches splayed out from the center.

Unfortunately, there’s not much you can do to prepare your tree for an early storm, aside from observing good pruning practices. But what you do after the damage is incurred is important.

According to Dr. Ray Maleike, retired Washington State University Extension Horticulturist, When snow or ice bend branches and entire trees out of shape, the…snow or ice should be removed immediately and an attempt made to straighten the bent branch or trunk.  If the plant part isn’t straightened very soon after the snow has stopped, the plant may remain bent over… permanently.”

uprooted tree in snow storm

An uprooted tree in Massachusetts

Remove the snow with a broom as best you can, moving in an upward motion, so you don’t put more tension on the limb. If the limb is packed with ice, let nature take its course. Trying to remove ice may cause more harm to the tree.

In the case of arborvitae, some branches may be bent out from the plant. To get the plant’s shape back, carefully remove any snow, freeing the branch and lifting it upwards. You may have to tie the bent branches to the main stem of the tree or bush to get them to grow back in correctly. Use soft cotton clothesline and leave it in place well into spring. Tying the arborvitae plants together like this can be a good preventative before winter arrives.

If a small tree has bowed over, but is not broken or split, try staking it with two stakes, about eight inches away from the trunk, being careful not to sever the roots. Tie the trunk of the tree to the stakes at the lowest point, which will stabilize the tree in an upright position. When the tree is able to stand on its own again, remove the stakes. This will usually be during the first growing season after the damage occurred.

About Todd Heft

Todd Heft is an organic gardener and freelance garden writer who lives in the Lehigh Valley, PA and has gardened for most of his life. When he isn't writing or reading about organic gardening, he's gardening. His first book, "Homegrown Tomatoes: The Step-By-Step Guide to Growing Delicious Organic Tomatoes In Your Garden" is available on Amazon now. Google
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One Response to Why Snow Causes More Tree Damage in Fall Than Winter

  1. Nate Armstrong says:

    I guess it would make sense that snow in the fall would cause more damage to trees than in the Winter. At first I was like, “No way.” and then I read that it’s because trees in the Fall still have their leaves so it’s because in the winter the snow passes right through.
    Very interesting!