The Marshall Fire that burned through Denver and Boulder, Colo. last week is estimated to have caused over $513 million in damage and destroyed almost 1,100 homes and structures, The Associated Press reports, per updates from Boulder County officials. It was the most destructive blaze in Colorado history.

Officials released the new totals after “further assessing” the damage in suburbs between Denver and Boulder; previous estimates marked at least 991 homes and other buildings destroyed. The $513 million financial figure is the first survey of the event’s economic damage, per AP.

Investigators are still working to determine the fire’s cause, but have narrowed in on an area near Boulder “where one person captured video of a burning shed just before the fire erupted,” reports The Hill. Officials believe it could take weeks to figure out exactly how the Dec. 30 blaze began.

Two people are missing, “though officials have found partial human remains at one location,” notes AP.

President Biden was slated to survey the fire’s damage on Friday.