These are some of my favorite government resources. I use and recommend them on a regular basis. They have provided me with exceptional value. Most of them have newsletters and real-time feeds. Subscribe!
A few are duplicated from the Hazards Central post but I thought it would be handy if you had them as part of this overall Golden Dozen.
Homeland Security: www.dhs.gov
National Weather Service: www.nws.noaa.gov
U.S. Cyber Security: www.dhs.gov/topic/cybersecurity
Emergency Alert Ready.gov Info: www.ready.gov/alerts
U.S. Centers for Disease Control and Prevention: www.cdc.gov
U.S. Citizen Corps: www.ready.gov/citizen-corps
U.S. Department of Energy: www.energy.gov
U.S. Department of Homeland Security: www.ready.gov
U.S. Environmental Protection Agency: www.epa.gov
U.S. Fire Administration: www.usfa.fema.gov
U.S. Nuclear Regulatory Administration: www.nrc.gov