Alerts & Conditions

Reds Meadow Valley Road

The road to Reds Meadow with access to valley destinations and Devils Postpile National Monument will reopen on September 16. Shuttle service has ended for the season. All visitors can drive to Devils Postpile, however, parking may be full from mid-morning to mid-afternoon each day. The $10/car standard amenity fee applies each day.

Devils Postpile Ranger Station is not open this year.


Harmful Algal Blooms

Recent testing yielded positive results for small amounts of toxic algae above and below Rainbow Falls in Devils Postpile National Monument, and toxic algae may exist in other sites in the monument. Toxins are concentrated within the algal mats themselves and released episodically into the water when the algae dies or is disturbed.

What does this mean for me?

  • For your safety, do not enter or drink in the area of Rainbow Falls.

  • Filtering and/or boiling the water is not effective against this type of algae.

  • Prevent pets from drinking the water and eating or touching algae in the water and dried on the shore. In particular, prevent dogs from eating dried algal mats on shore.

  • Please report any large algal blooms and/or algae that is particularly bright, bubbly, strange-looking, or appears like a haze in the water.

  • Do not disturb algal mats in any way. Wading or swimming can cause toxins to be released into the water.

  • If you suspect a site has toxic algae, do not enter the water and do not drink water from the area. While some sites are signed based on testing results, it’s likely that algae exists in other parts of Devils Postpile. Don’t rely on signage alone.

Can I still swim in the river? Can I still filter or treat the water for drinking?

Water that is clear with no visible algae in the area presents a low risk. Even in areas with no visible algae, watch for isolated clumps of algae floating by.

If you think algae may be in the water:

  • Do not enter the water.

  • Do not drink the water, even if treated.

  • Do not let pets into the water, allow them to drink the water, or eat algae on the shore.

What are the signs and symptoms of exposure to toxins from algae?

According to the California Water Quality Monitoring Council, the following signs and symptoms may occur within 48 hours of exposure to a waterbody with a suspected or confirmed algal bloom:

  • sore throat or congestion;

  • coughing, wheezing, or difficulty breathing;

  • red, or itchy skin, or a rash;

  • skin blisters or hives;

  • earache or irritated eyes;

  • diarrhea or vomiting;

  • agitation;

  • headache; and/or,

  • abdominal pain.

If people show symptoms of cyanotoxin and/or cyanobacteria exposure after contact with water, or with scums or mats of algae, they should receive immediate medical attention. Additional resources are available from the Centers for Disease Control and Prevention (CDC), and by contacting the California Poison Control Center (1-800-222-1222). See the HAB-related Illness Tracking webpage for information on previously reported human illnesses related to HABs in California.

Is the National Park Service monitoring for harmful algal blooms?

The park continues monitoring for toxic algae and testing for toxins throughout the park. You can learn more about harmful algal blooms at


Historic Public Opening and Closing Dates of Reds Meadow Road

Below are the dates that the Reds Meadow Road, the only road to access the monument, opened and closed each year since 2000. Note that the monument has been open to the public on Memorial Day weekend in only three of the past twenty years.





2021 June 17 ? No shuttle service until July 2


June 26

September 7

Closed early due to the Creek Fire


July 4

October 27


June 16

October 9


July 21

October 29


June 18

October 30


May 22

October 26


June 12

October 31


May 24

October 1

Closed 10/1-16 due to shutdown.
Reopened 10/17-30


June 29

October 18


June 29

October 31


June 24

October 12

Several storm closures prior


June 6

October 20


June 6

October 30


May 26

October 30


June 27

October 31


June 29

October 17


June 12

October 16


June 13

October 30


June 14

October 31


June 7

October 30


June 10

October 26

Several storm closures prior

Last updated: September 14, 2021

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PO Box 3999
Mammoth Lakes, CA 93546


(760) 934-2289

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