Fumaroles

Mono County, California · Near Mammoth Lakes
37.6220°N, 119.0280°W · 8,167 ft
Hot 40°F air · Good soaking weather 8,167 ft Open Short Walk US Forest Service Camping nearby (1.6 mi)
Fumarole: Not a Soaking Spring

Fumaroles is a fumarole, not a traditional hot spring. These geothermal features can be extremely dangerous. Boiling water, toxic gases, and unstable ground are common hazards. Do not attempt to soak.

A group of fumaroles, steam vents with no pool, on Inyo National Forest land about two miles from Mammoth Lakes. Access is open. No water temperature is on file, only a remark that the ground runs hot. Nothing to soak in. The USGS tracks the site. Lake Mary Campground is close.

Location

High in the Sierra, a third of a mile or so from the nearest road, on Inyo National Forest land. Snow is enormous here, around sixteen feet a year, and the cold holds for most of the calendar. Lake Mary Campground and the town of Mammoth Lakes are both near.

No best months are listed. Given the snowfall, time a visit for the snow free months. Forest Service ground, open, with no fee on record. There is no pool and no temperature, so come to look. Lake Mary Campground is right there. The USGS keeps a site record for the vent field.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around Fumaroles.

Aerial view of the ground around Fumaroles LiDAR bare-earth view of the same ground around Fumaroles
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

Setting
Hillside
The spring sits on a steep slope that climbs to the north.
Highest ground nearby
817 ft above the spring
Within a quarter mile, to the north
Cross-section through the spring

A slice through the ground from north to south, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
126 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 77% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
21°
Jan
19°
Feb
23°
Mar
28°
Apr
34°
May
47°
Jun
54°
Jul
53°
Aug
47°
Sep
38°
Oct
27°
Nov
18°
Dec
Annual Precip: 32.8 in Annual Snow: 199.8 in
Current Conditions
40°F
29% Good soaking weather
Tuesday 56° Low 39° Sunny
Wednesday 52° Low 36° Sunny
Thursday 52° Low 34° Sunny
Friday 56° Low 35° Sunny
Saturday 58° Low 39° Sunny 1% precip
Where to Stay

Some links are affiliate links. We may earn a commission at no extra cost to you.

Nearby Camping
Lake Mary Campground 1.6 mi away

Overview Lake Mary is the star of the Mammoth Lakes region. Of the 11 lakes in the area, Mary is the largest and most developed. Lake Mary Campground is a large facility with plenty of amenities in and around it. The lake provides a great base for activities like fishing, viewing waterfalls, hiking and backpacking.Recreation Lake Mary receives the highest number of trout stocks in the Mammoth Lakes Basin, and is well-known to anglers for its rainbow, brook and brown trout fishing. No swimmin...

Reservable Yes
Reserve on Recreation.gov →
High Altitude Advisory 8,167 ft

At 8,167 feet, Fumaroles is in high-altitude territory where the air is noticeably thinner. Soaking in hot water accelerates dehydration and can amplify altitude effects like headache and fatigue. UV radiation is roughly 33% stronger here. Wear sunscreen even on overcast days and take breaks from the water to rehydrate.

As an Amazon Associate, we earn from qualifying purchases.

Temperature
Hot
Warm Hot Boiling
Avg Air Temp 34°F
Access
Open
Road Access Short Walk
Distance to Road 0.3 mi
Land
Ownership Federal
Agency US Forest Service
Designation National Forest
Unit Inyo National Forest
Manager US Forest Service
Protection 3 - Protected, subject to extractive use
Frequently Asked Questions
What is the water temperature at Fumaroles?
Fumaroles is classified as hot. An exact temperature measurement has not been recorded.
Where is Fumaroles located?
Fumaroles is located in Mono County, California at 8,167 feet elevation, near Mammoth Lakes. Coordinates: 37.6220°N, 119.0280°W.
How do I get to Fumaroles?
Fumaroles has Short Walk road access (0.3 mi from the road).
Is Fumaroles free to visit?
Fumaroles has Open access. It is managed by US Forest Service.
Can I camp near Fumaroles?
Yes, Lake Mary Campground is located nearby (1.6 miles away).
Sources: USGS NWIS