@bereadyherriman on their city's website.
A live ammunition exercise at Camp Williams, located on the county line between Salt Lake and Utah County, caused the fire to start at about 12:30 pm. Three hours later, when it became apparent that they would not be able to contain the fire, the military notified the Utah Fire Authority of the blaze. At about 5pm MST, the city began tweeting when it first became apparent that this fire might start to grow:
Per Herriman City, CERT teams please be on standby due to fire south of Herriman. NO ACTION IS REQUIRED AT THIS TIME."
The CERT teams were alerted.
Several official Twitter channels, including @HerrimanCity and @Utahgov began to share updates. Within a few hours, the dynamics of the situation had changed dramatically.
Everything south of Emmeline, Butterfield Parkway and Blackridge reservoir is now being MANDATORY evacuated. That's south of 14200 South.
Prior to that mandatory evacuation order issued over Twitter by city emergency officials, a shelter had been set up at the junior high school and then moved to the high school, evacuation routes were shared over Twitter, instructions were issued for evacuating animals the the county equestrian park, and FEMA had responded with support from the region. Governor Herbert was also responding on his Twitter channel and was on site. The common use of the #Herrimanfire hashtag made it easy to track all the traffic related to the fire.
In addition to Twitter, maps were posted to Google Maps and YouTube was used to share personal video of homes burning which were used by the media. When the city's website became stressed, citizens responded by reposting key information, like maps of the evacuation routes on sites like DropBox. At the same time, citizens were reminded by officials like @UT_MIT "Please do not self-deploy as a volunteer #Herrimanfire" and traffic management instructions were issued. Citizens posted photos and information to Flickr and other sites:
Reporters from traditional media channels, like @BenWinslow also became very active in the conversation and getting information out to the public:
By this morning, the situation was more under control, about 10,000 acres had burned, more than 1600 homes were evacuated, four homes had burned to the ground. Seven area schools were closed and residents were notified via Twitter. Governor Herbert flew in a helicopter over the area to survey the situation. At about 7:30, he posted to Twitter:
Guv says 4 Blackhawk helicopters ordered to help. "Today looks very good for us to get this fire out." @fox13now#Herrimanfire #Utah
Just landed after aerial tour of #Herrimanfire. An amazing scene, firefighting efforts are making a difference, even over last night.
Finally, Utah had one more example of the effectiveness of social media in helping to respond to a significant emergency.