When the NCAR fire broke out Saturday afternoon, many Boulder County residents who didn’t need to evacuate received public safety alerts on their cellphones, causing confusion in Superior and Louisville, where there was no danger.

Some people were tweeting that the fire was nowhere near their homes and wondering why they were getting the notices.

The NCAR fire broke out near the National Center for Atmospheric Research and was mostly active around South Boulder. At one time, the evacuation zone included as many as 19,400 people. But many Marshall fire victims who live in nearby areas and received the Wireless Emergency Alert were traumatized by the possibility of having to evacuate twice in three months.

Boulder County issued a statement to residents, saying: “We have received several complaints that individuals well outside of the evacuation zone, including in neighboring communities, received these. This spill over is a well-known issue and currently is hard to avoid.”

NCAR fire in Boulder is 68% contained

The situation was quickly eradicated as officials working in real time released maps, used social media and notified local news outlets to clarify who needed to evacuate and who didn’t. 

The WEA system, which Boulder County put in place two weeks ago, is one of two systems the Boulder Office of Emergency Management uses to notify people of natural disasters and other emergency situations like shootings and hazardous material spills. It is managed federally and operates off of cellphone towers. As a result, the notification, which sounds exactly like the Amber Alert, will reach anyone who is within range of a tower.

“With WEA, you don’t have to opt-into the system. But since it uses cellphone towers, it will grab any cellphone pinged to that tower,” city of Boulder spokesperson Sarah Huntley said. “With WEA, you’re likely to be alerting more people than you need to.”

Huntley says WEA’s far reach can also be a public safety risk because it can clog already-busy evacuation routes. 

Boulder has a second emergency system called Everbridge, which was in place during the Marshall fire. Everbridge reaches landlines and requires residents to opt-in with their cellphone numbers. Some residents in unincorporated Boulder County, Superior and Louisville didn’t get those notifications because they hadn’t opted-in through the county.

Huntley said that when it came to the WEA cellphone range, Boulder emergency officials had to rely on social media to find out who was getting notifications because WEA reaches such a large area.

“We don’t have the ability to tell cell towers which phones to ping,” she said, adding that there was a tweet from a person from as far away as Cheyenne who got a WEA ping.

Boulder authorities used WEA in tandem with Everbridge for the first few hours of the NCAR fire in order to get people’s attention. They then dropped WEA once evening set in.

“It’s important to err on the side of caution,” Huntley said of why Boulder County now uses two alert systems. “But I’m sure it caused emotional distress and confused people.”

Authorities are tweaking the evacuation maps generated by Everbridge and WEA. The two maps were slightly different and also caused some confusion among homeowners, some of whom were on one map but not on another.

Residents were allowed to return to their homes by 5 p.m. Sunday. The NCAR fire burned nearly 200 acres and was 35% contained as of Monday afternoon.

Opt-in to Boulder County’s Everbridge system at bouldercounty.org/safety/emergency/emergency-mass-notification-system.

For more information on WEA, visit fcc.gov/consumers/guides/wireless-emergency-alerts-wea.