The National Weather Service office in Great Falls issued a Flash Flood Watch early Thursday morning covering portions of southeast Lewis and Clark County and northwest Meagher County, with the watch running through midnight Friday. The concern is focused on the Horse Gulch Burn Scar, where stripped hillsides leave little to absorb a hard rain before water and debris start moving fast.
Forecasters are tracking afternoon and evening thunderstorms capable of dropping heavy rain in a short window directly over the burn scar. That combination — intense localized rainfall on fire-scarred ground — is exactly the scenario that produces debris flows with little warning. Residents and recreationists near Horse Gulch should monitor conditions closely and have a plan to move to higher ground quickly if storms develop nearby.
The watch was posted at 12:23 a.m. MDT July 17. Burn scars from previous fire seasons in Lewis and Clark County have generated flash flooding events in prior summers, and the NWS Great Falls office has flagged this area as particularly vulnerable when thunderstorm activity tracks over it. Anyone traveling rural roads in the affected area should check conditions before heading out and avoid crossing flooded washes, even ones that appear shallow.