Strong to severe thunderstorms are possible from the central Plains to the Northeast through this evening. Widespread damaging winds are the primary threat but hail and a tornado or two is also possible. Extremely dangerous heat continues across the Eastern U.S. Warm overnight low temperatures will provide little to no relief. Read More >
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Two flood waves hit the Supai area late on July 11th. The first (and most damaging) occurred around 7-7:30pm (the other was later that night). Serious flooding occurred in the Supai campground, with reports of a 7’ rise in Havasu Creek. The media reports of a ‘7 foot wall of water’ hitting the area is consistent with gauge data, with a 4’ rise at the Supai Gauge (850 CFS), and an 8’ rise downstream at the Colorado River (3760 CFS). The last Supai flood event of a similar magnitude occurred during the afternoon/evening of 26 August 2013. It is estimated that Havasu Canyon will be closed from 7-10 days due to the damage.
Radar Loop July 11th From 4:13pm To 7:16pm
Storm Total Precipitation July 11th From 4:13pm To 7:16pm
Radar Estimated Rainfall from 5pm - 8pm July 11th
Radar Estimated Rainfall from 12pm - 3am July 12th
Flood Event #1: July 11
Flood Event #2: July 12
Two flood waves hit the Havasu Creek gauge at Supai
Flood waves were recorded at the gauge on Havasu Creek near the mouth
Cataract Creek at Heather Wash recorded a roughly 3 foot rise
A significant rise of around 7 feet was recorded at the Cataract Creek gauge below Topocoba
By mid-day on July 11, 2018, surface and mid-level south to southeast winds associated with the desert Southwest monsoon created conditions favorable for the formation of scattered thunderstorms over the Cataract Creek drainage basin. These thunderstorms contained enough monsoonal moisture to cause rainfall of up to 1 – 1.5” over Cataract Creek and washes that drain into the creek. Eventually, the flood waters traveled far enough downstream to result in the flash flooding of Supai Creek (represented by the hydrographs above).
For more information on impacts and general inquiries about this event, please reference the contacts below: