Rule of 3 for Wilderness Survival

Many people followed closely James Kim tragedy. James was a San Francisco man who sought help for his stranded family, got lost in the snowy Oregon wilderness and died of hypothermia.

According to CNN:

You can survive for 3 hours without shelter
You can survive for 3 days without water
You can survive for 3 weeks without food

References:
Wilderness survival: The rule of threes. Anderson Cooper 360 degrees blog.
A Winter Tragedy. Paul Auerbach, MD. Medicine for the Outdoors.
Kim died close to food, shelter, officials say. CNN.com.