Lynn Ann Michel was allegedly driving under the influence when she plowed her 2005 Isuzu SUV into a flock of sheep on a county road in Rio Grande County, Colorado, before driving away.
Initially, the death toll stood at 38, with 12 injured, but that number was updated two days later.
The 47-year-old driver now faces charges of DUI, leaving the scene of an accident involving property damage, and no insurance, according to the Colorado State Patrol.
The woman, hailing out of Monte Vista, was tracked down by her license plate which had fallen off at the scene.
She was later released on a summons.