HomeGuidesIce and wind storm tree prep
Portland General Electric's review of the January 2024 ice storm named Beaverton, Tigard and Lake Oswego as the hardest-hit places in its territory. About 440,000 customers lost power that week, largely because of trees and branches on lines. Most of what broke could have been predicted in October.
By Harry Fauver, founder of Tree Service Beaverton. Updated September 2026.
The Tualatin Valley gets a particular kind of winter storm. Cold air drains out of the Columbia Gorge and pools on the valley floor, a warm Pacific system rides in over the top of it, and rain falls through the cold layer and freezes on contact. A quarter inch of ice is a nuisance. Half an inch to an inch, which is what January 2024 delivered in places, can multiply the weight a branch carries many times over.
Wind breaks trees where they are weakest. Ice is different, because it loads the whole crown at the same time, and it loads horizontal branches most. Add an east wind on top and trees that have stood through forty winters come apart in an afternoon.
Our storms come in two types. Ice, in December and January, breaks limbs and splits trunks. Wind on saturated ground, any time from November to March, tips whole trees over at the roots. They call for different preparation, and this guide covers both.
Pick a tag. Every one of these can be seen from the ground in October.
A limb that reaches far out to the side, with most of its foliage at the end, is a long lever. Ice adds weight exactly where it does the most harm. Shortening the limb back to a good side branch, called end-weight reduction, is the most effective storm pruning there is.
Where two stems of similar size meet at a tight angle, bark gets trapped between them and the joint never knits. Ice pries the two halves apart. On a young tree, one stem is removed or subordinated. On a mature tree, weight is reduced on both sides, and a cable is sometimes added high in the crown.
Dead branches are dry, brittle and already halfway to the ground. Ice brings them down first, and they take live branches with them. Removing dead wood from trees over roofs, driveways and walks is simple insurance, and it can be done in any season.
Tall arborvitae are made of many upright stems held together by nothing but foliage. Ice pushes them apart and they rarely close again. Keeping hedges shorter, and tying the stems of tall ones together inside the foliage with soft strapping before winter, saves most of them.
The insulated line from the pole to your house is your responsibility to keep clear, and it is the line most often pulled down by a falling limb. Have branches above it shortened before winter. PGE can disconnect it for the day so the work is done safely. The bare lines along the street are PGE's to prune.
What to do, and when.
Walk the yard with the five failure points in mind, and look hardest at anything that could land on the house, the driveway, the service line or the neighbor. Book pruning now. After the first storm every tree service in the county has a waiting list. Clean gutters and clear the storm drain out front, and note where your main electrical panel and gas shutoff are.
Move cars out from under trees and into the garage or the open. Bring in or tie down anything a falling limb could turn into a projectile. Charge phones, and find the flashlights. Do not try last-minute pruning from a ladder. If small shrubs and young trees matter to you, tie their stems loosely together.
Stay indoors and away from rooms directly under large limbs if the ice is heavy. You will hear limbs crack before they fall, often hours apart. Do not go out to knock ice off branches: frozen wood snaps, and the branch overhead is the one that falls. Treat every downed or sagging wire as live, stay 50 feet away, and call 911 and PGE at 503-464-7777.
Look up before you walk anywhere. Broken limbs hang in crowns for days and fall when the ice melts and the wood flexes back. Photograph damage from a safe distance. If a tree is on the house, a car or blocking the way out, call us. Leave bent-over young trees alone, because many straighten by themselves once the ice is gone.
Ragged breaks should be cut back cleanly to the branch collar so the tree can close them. A tree that has lost less than half its crown usually recovers. One that has split down the trunk usually doesn't. Be wary of anyone going door to door offering to top what is left. Topping is how the next storm's damage gets made.
Helps: removing dead and broken wood, shortening overextended limbs back to a side branch, reducing weight evenly on both sides of a weak fork, and structural pruning of young trees so that weak forks never form.
Makes it worse: topping, which replaces a tree's structure with a thicket of weakly attached sprouts that hold ice like a broom. And lion-tailing, where the inner branches are stripped and foliage is left only at the tips. That moves weight to the end of every limb, which is precisely where ice does its damage.
The best time for storm pruning is late summer through fall, before the rain sets in and well before the first freeze. See tree trimming and maintenance for how we do it.
By December the valley's clay soils are saturated and grip roots poorly. A strong wind from an unusual direction, especially the east wind out of the Gorge, pushes on trees that grew up braced against southwest storms. That is when whole Douglas-firs go over, root plate and all.
Our guide to signs a tree is dangerous covers these in detail.
No. Frozen branches are brittle and snap when struck, and the limb most likely to fall is the one above you. Leave the ice to melt. Many bent branches and young trees straighten up within a few days.
Ornamental pear, sweetgum, birch, bigleaf maple, willow and cottonwood, plus tall arborvitae and other multi-stemmed evergreens. Trees with one main trunk and well-spaced limbs, including most conifers and oaks, do much better.
Light thinning does little. What helps is removing dead wood and shortening long, heavy limbs. Stripping out the inner branches makes things worse, because it moves weight to the branch tips, where ice does the most damage.
Late summer through fall. Dead wood can be removed at any time. Book early, because after the first winter storm every tree service in Washington County is busy with emergencies for weeks.
Often, yes. A tree that keeps about half of its crown and has an intact trunk usually recovers over a few years once the broken ends are pruned cleanly. A trunk split down the middle is a different matter and usually means removal.
Tell us about the tree and we'll call to set up a site walk. For emergency service, skip the form and call.
