Regional Severe Weather
Rocky Mountain Hail Guide: High Plains Storms, Upslope Flow, and Large Hail
Why hail is common near the Rockies and High Plains, including upslope flow, cold air aloft, supercells, and fast storm growth.
Quick answer: The Rockies and adjacent High Plains can support large hail when upslope moisture, instability, and strong winds aloft overlap.
Upslope flow
Low-level winds pushing moisture toward higher terrain can help storms form and intensify.
Storms may then move east into the Plains.
Hail growth
Cold air aloft and strong updrafts help hailstones grow inside thunderstorms.
Large hail can occur even when tornado risk is low.
Preparedness
Vehicles, roofs, skylights, crops, and livestock are vulnerable to hail.
Move indoors and away from windows during severe warnings.