Damaging winds can come from thunderstorms or sudden onset "microburst" winds that are difficult to predict. When these winds exceed 50 mph, they are considered damaging winds. NOAA's National Severe Storms Laboratory conducts research on damaging wind events.
Straight-Line Winds vs. Tornadoes
Damage from straight-line winds spawned from thunderstorm cells is far more common than damage from tornadoes. Downbursts (straight-line winds) form when rising air cools until water vapor condenses into cumulus clouds. When air becomes over-saturated, cold air descends to the earth's surface, producing a dramatic increase in winds — some that exceed tornado-force winds.
See Straight-line winds vs. tornado comparison — weather.gov.
Preparedness
Most preparedness measures for straight-line and tornado winds are fairly similar, with some overlap with hurricane preparation procedures. Wind-borne objects can cause significant damage independent of the wind force alone. Storm cells producing straight-line winds may also produce damaging hail, which can impact homes, vehicles, and crops.