It is my understanding Lahar flows are caused by volcano activity. Rather than lava molten rock, lahars are mud and hot water mix. Flash floods are caused by rain water. NOTE: if Mt Rainer (Washinton state), blows again the main concern is a Lahar that would place Tacoma, pullayllup and that area in the path of a Lahar. Hope this helps.
Thank you for the info.
I remember Mt. St. Helens and the wall of burning mud that destroyed everything downstream. Would that then be a lahar flow?