storms/tornadoes

What happens to warm, moist air when it rises?

It expands, cools, and condenses into clouds.

What happens when a cold air mass collides with warm, moist air?

Cold air forces warm air upward, forming cumulonimbus clouds and thunderstorms.

Which is heavier: dry air or moist air?

Dry air.

What causes lightning?

Charge separation from falling ice and rising water molecules.

What causes thunder?

Lightning rapidly heats air, causing it to expand explosively.

What causes hail?

Ice repeatedly lifted above and below the freezing line until heavy enough to fall.

What distinguishes supercells from other thunderstorms?

They form a rotating mesocyclone capable of producing tornadoes.

How do supercells form?

Wind shear forms a horizontal vortex → lifted upright → rotation intensifies into a mesocyclone.

Which way does wind blow near a tornado?

Winds blow inward at ground level and outward above 100 ft.

Why is the Midwest productive for tornadoes?

Cold northern air + warm Gulf air + dry SW air + strong jet stream.

How many tornadoes occur annually in the U.S.?

About 1,000.

What is the prime U.S. tornado season?

Spring.

How does the EF Scale rate tornadoes?

By damage used to estimate wind speed.

Can fixed Doppler radar easily measure tornado wind speeds?

No — it measures winds too high above the surface.

Can tornadoes have multiple vortices?

Yes, multiple subvortices are common.

Where should you shelter indoors during a tornado?

Basement or interior room with no windows.

Where should you shelter outdoors during a tornado?

Drive away if possible; otherwise lie in a ditch. Avoid overpasses.

What is the biggest danger from tornadoes?

Flying debris.