San Gabriel Mountains · Alpine summit
Mount Baldy via Devil's Backbone
A demanding climb to 10,064-foot Mount San Antonio, using the broad Notch approach and an exposed ridge above the Los Angeles basin.
Photo: Skouyoum · CC0 1.0CONDITIONS DESK
Read the sky.
Pack the water.
Use this as planning context, then open the live point forecast on the morning of your hike. Weather and natural water can change faster than a guide page.
WEATHER
What to watch
Use the summit forecast—not the Los Angeles basin forecast—and check wind, temperature, precipitation, snow level, and lightning. Conditions can deteriorate rapidly above Baldy Notch.
OPEN NWS POINT FORECAST ↗Mount San Antonio summitCLIMATE
How the year behaves
This is high-elevation mountain terrain with cold winters, persistent snow and ice, strong ridge wind, and large temperature swings. Even in summer, the summit can be much colder than Manker Flat.
Best season: Snow-free conditions for experienced hikersWATER SOURCE
Carry all water
Seasonal falls and drainages are not a dependable or potable supply. Carry enough from the trailhead for the full climb and descent; do not assume services at the Notch will be open.
Carry all waterForecasts are informational. Check official closures, alerts, fire restrictions, and the managing agency before every trip.
This is one of Southern California's defining summit days and one of its least forgiving. The route combines a long fire-road climb, high-elevation exposure, loose trail, and almost 4,000 feet of gain before a steep descent through Baldy Bowl.
ROUTE WALKTHROUGH
What the hike is like
- From Manker Flat, climb the paved and dirt service road past San Antonio Falls toward Baldy Notch.
- Continue above the Notch to the Devil's Backbone ridge, then follow the crest toward Mount Harwood and the Mount Baldy summit.
- A common loop descends the Baldy Bowl/Ski Hut Trail. It is steep, loose, and easy to underestimate late in the day.
BEFORE YOU DRIVE
Planning the day
- Treat the listed mileage as a full mountain day and preserve time, water, and leg strength for the descent.
- Weather at 10,000 feet can be dramatically colder and windier than the trailhead.
- Verify current Angeles National Forest orders, road access, and ski-area operations before leaving.
TURN-AROUND JUDGMENT
Safety that matters here
- Winter and spring snow turn this into mountaineering terrain. Microspikes alone are not a substitute for ice-axe, crampon, and self-arrest skills when slopes are firm.
- The Devil's Backbone is exposed. Avoid the ridge in high wind, lightning, ice, or when your group is uncomfortable with drop-offs.
- Altitude illness can begin below the summit. Descend if headache, nausea, confusion, or poor coordination develops.