Videos Section

2011 How Do We Know

How Do We Know: Tracking Tornadoes Watch Video

How Do We Know: Tracking Tornadoes

How do we know when a tornado is forming? Scientist Harold Brooks explains how Doppler radars are used to track storm formation.

How Do We Know: Shrinking Arctic Sea Ice Watch Video

How Do We Know: Shrinking Arctic Sea Ice

Learn how NASA scientists are tracking the melting Arctic sea ice and what less ice means for global warming in the future.

How Do We Know: Hurricane Hunting Watch Video

How Do We Know: Hurricane Hunting

National Hurricane Center scientist Jack Beven explains the technology used to forecast and track potential hurricanes as they happen.