Riverside County—Early Warnings: For emergency events or disasters—will alert land lines only. The primary phone number for every business and residence in Riverside County who has traditional phone service, whether it is a listed or unlisted phone number are part of the EWNS. You may add other types of numbers such as your cell phone, by visiting the Riverside County homepage; www.countyofriverside.us. Click on the EWNS link. Emergencies include wildfires, floods, hazardous materials, severe weather, and law enforcement incidents.