When forecasts call for a hazardous change in the weather, meteorologists issue warnings to stay off the road and seek shelter immediately. Weather alert apps make it easier than ever to avoid driving in dangerous conditions, or to get caught in storms, such as hurricanes and blizzards. The Red Cross has apps for specific dangerous weather situations you might encounter. Weather Underground offers apps for Android and iOS devices. The National Weather Service lets you easily add its mobile site to your device's home screen.