How to Tell If a Tree Is a Storm Risk Before the Next Big Wind Event

Our emergency line gets its busiest stretch every year in the days right after a major wind event, and almost every call follows the same pattern: a tree that had been showing warning signs for months, sometimes years, finally came down. The frustrating part is that most of these failures were predictable — not certain, but predictable — if someone had looked at the right things beforehand.

Why this matters more here than in a lot of places

Northern Michigan gets a specific combination of stressors that other regions don’t deal with together: straight-line wind events off Grand Traverse Bay and Lake Michigan, heavy wet snow loads that add enormous weight to a canopy, and — over the last decade — a wave of dead and dying ash trees from emerald ash borer scattered throughout otherwise healthy-looking properties. Any one of these can push a compromised tree past its breaking point.

The warning signs worth taking seriously

A visible lean, especially a new or increasing one. Some trees have grown with a natural lean their whole life and are perfectly stable. What matters is whether the lean is new, or whether you’re noticing lifted soil or cracking on the side opposite the lean — that combination usually means the root system is failing, not just that the tree grew crooked.

Exposed or damaged roots. Construction work, grade changes, erosion, or storm damage can expose or sever roots that were providing critical structural support. A tree that looked completely stable for years can become a serious risk after root damage that isn’t obvious from a casual look at the canopy.

Cavities and decay at the base or in major limbs. Not every cavity means a tree is doomed — trees can compartmentalize decay and remain structurally sound for years. But a large cavity, especially combined with fungal conks (mushroom-like growths) at the base, is a sign that needs a professional assessment, not a guess.

Dead or dying major limbs, especially over the roof or driveway. Deadwood is more brittle and more likely to fail than live wood, and it doesn’t need a major storm to come down — sometimes just its own weight in wet snow is enough.

Codominant stems with included bark. When a tree has two main trunks splitting from roughly the same point with a narrow, V-shaped union rather than a wide, U-shaped one, that union is structurally weak and prone to splitting apart under wind or snow load, often without much warning.

Cracks in the trunk or major limbs. Any visible crack running with the grain of the trunk or a major limb is a sign of a structural failure already in progress, not a cosmetic issue.

What to actually do about it

If you’re seeing one or more of these signs on a tree near your house, a car, or anywhere people regularly walk or park, that’s worth a professional assessment before the next major wind or snow event, not after. An ISA-certified arborist can tell you whether what you’re seeing is a real structural risk or a tree that’s simply grown in an unusual but stable way — and if it is a risk, whether pruning to reduce the hazard is enough, or whether the tree needs to come down.

The honest tradeoff

We understand nobody wants to remove a mature tree, and we don’t recommend it lightly — a lot of what we do in a health assessment is figuring out whether a tree everyone assumes is dangerous is actually fine. But the trees that fail catastrophically in storms are rarely trees that gave no warning at all. If something about a tree on your property has been nagging at you, that instinct is usually worth listening to.