Valley Forge National Historical Park

Severe thunderstorms are the standout hazard at Valley Forge National Historical Park, with 14 recorded thunderstorm wind events logged in Montgomery County — more than double any other weather threat in the data. Those fast-moving storms routinely down trees and scatter debris across the park's open fields and wooded trail corridors, and six hail events add another layer of risk for anyone caught outside without shelter.

When the forecast shows afternoon storm potential, plan your hike or bike ride along the Grand Parade field for morning hours and identify the nearest hard-sided building — the park's visitor center is your best refuge — before you head out. Pack a weather radio app with push alerts enabled, since cell signals can be unreliable in the creek valleys. If you hear thunder, get off the open fields immediately; the wide, treeless grounds that make Valley Forge iconic also make you the tallest object around during a strike.