A fourth firefighter has died from burns sustained after being overcome by a fast-moving wildfire last month near the Colorado-Utah border. Nathan Matthews, 43, died Friday, the federal Interior Department announced.

Matthews was part of a Helitack crew deployed to Mesa County, Colorado, west of Grand Junction, on June 27. The crew was responding to a rapidly expanding wildfire when they were engulfed in what officials described as a burnover, a situation where fire overtakes all escape routes. The firefighters attempted to shield themselves in emergency shelters.

Three firefighters – Emily Barker, 38, Nick Hutcherson, and Sydney Watson, 26 – died at the scene. Matthews and another firefighter were transported for medical treatment following the incident. An update on the condition of the other injured firefighter was not immediately available.

Watson, Hutcherson, and Barker were honored at a memorial service earlier this month. Memorial arrangements for Matthews have not yet been announced.

The western United States has experienced numerous large fires this summer. Factors contributing to the blazes include prolonged dry weather, a significant lack of snowpack in some regions, high temperatures, and unpredictable winds. Firefighters were preparing for potentially worsening conditions in Oregon, where a wildfire near Bend was a concern due to its proximity to populated areas.