Emergency supplies should include at least a 3-week supply of water & non-perishable food, and a battery-operated NOAA Weather Radio.  NWR is an all-hazards radio network, making it the most comprehensive weather and emergency information available to the public.

All-Hazards Emergency Messages on NOAA Weather Radio
NWR broadcasts National Weather Service (NWS) warnings, watches, forecasts and other non-weather related hazard information 24 hours a day. During an emergency, NWS forecasters interrupt routine broadcasts and send a special tone activating local weather radios. Weather radios equipped with a special alarm tone feature sound an alert to give you immediate information about a life-threatening situation.
 

NWR broadcasts warnings and post-event information for all types of hazards: weather (e.g., tornadoes, floods), natural (e.g., earthquakes, forest fires and volcanic activity), technological (e.g., chemical releases, oil spills, nuclear power plant emergencies, etc.), and national emergencies (e.g., terrorist attacks). Working with other Federal agencies and the Federal Communications Commission's (FCC) Emergency Alert System (EAS)
 

Life-threatening weather emergency messages are alerted on NWR. Many of those same weather-related emergency messages are also broadcast via the EAS.