The National Weather Service will soon start sending severe weather warnings to millions of smartphone owners in the U.S., the Associated Press reports. Wireless Emergency Alerts will warn users about the following threats — tornadoes, hurricanes, typhoons, tsunamis, flash floods, extreme winds, blizzards and ice and dust storms. A warning, which will show up to all users in a county, will include a message with no more than 90 characters, and late-model smartphones will sound a special tone and vibrate. The system will be free and it will not require users to sign up for the service. Read the full story at Mashable.