Visitors to Mt. Graham are advised to use extra caution due to monsoonal storms and increased potential for flooding.
Heavy rainfall may cause downstream flooding of streams, canyons, roads and trails during and after storms. On Mt. Graham, runoff and flooding may be accelerated from the burn scar of the 2017 Frye Fire, as vegetative cover has been lost and water, soil, rocks and woody debris may move swiftly downslope without warning.
Of particular concern is the area above Frye Mesa, where runoff collects into temporary pools. Flash flooding from storms upstream may occur in this and other locations. Recreationists are cautioned to avoid the area when storms may be present there or higher up in the watershed.
Only one access route, Swift Trail, is available for travel up and down Mt. Graham. Should the road become compromised, emergency road closures and delays are possible. Motorists are encouraged to drive slowly, watch for hazards, carry extra food, water, flashlights, warm clothing, and be prepared for temporary delays which could take hours for road-clearing.
Wet Canyon presents a high potential for flooding on Swift Trail. Campground flooding and road damage to Swift Trail have occurred at Hospital Flat, in addition to roadway and culvert damage at Grant Creek. Temporary repairs have been made at both locations, but both are subject to continued flooding due to post-fire conditions. The gate at Hospital Flat has been temporarily closed until safety issues can be addressed. Campers may use the adjacent dispersed recreation sites at Hospital Flat.
Visitors are advised to check weather forecasts for areas they intend to visit and plan accordingly. Thunderstorms can develop quickly and may bring heavy rain, hail, lightning and strong winds. Flooding downstream from storm cells is common.
Tips for lightning and flooding safety:
- Postpone activities when storms are in the forecast to prevent being caught in a dangerous situation.
- Select campsites that are on high ground, away from stream banks, washes and low-lying areas.
- When outdoors, monitor the weather and watch for signs of thunderstorms.
- Develop a lightning safety plan by knowing where to go for safety and the amount of time needed to get there.
- If thunder can be heard, lightning may strike. Seek shelter in an enclosed building or hard-topped vehicle. Avoid open areas and trees.
- Rain falling high in the mountains will drain downhill, and may cause flash flooding below areas where rain is falling. Rain does not need to be falling at a specific location for flooding to occur there. Avoid low-lying areas, streams and slot canyons during and after storms.
- If flooding occurs, seek safety on higher ground.
Planning ahead and using situational awareness are recommended to prevent monsoon storm-related emergencies.