Snow-eater heat waves are pretty much like they sound — abrupt snowmelt triggered by rain-on-snow and followed by several days of unseasonably high temperatures. “Seven of 11 spring super floods are shown to coincide with snow-eater heat waves. The authors noted that in the spring and early summer in the West, heat waves occur regularly. Snow-eater heat waves are caused by a buildup of abnormally high pressure that diverts storms, acting like “a boulder in a stream,” said Rhoades in an email to Courthouse News. Rhoades said snow-eater heat waves have occurred often over the last few centuries, but a particularly impactful one just happened in March 2026.