• Giant Sequoia Trees

    Sequoia & Kings Canyon

    National Parks California

There are park alerts in effect.
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  • The Generals Highway "Road Between the Parks" is OPEN

    The section of road between Lodgepole (Sequoia) and Grant Grove (Kings Canyon) is open. Call 559-565-3341 (press 1, 1) for 24-hour road updates.

  • Be Prepared! Tire Chains or Cables May Be Required in the Parks at Any Time

    All vehicles must carry chains or cables when entering a chain-restricted area. It's the law (CA Vehicle Code, Section 605, Sections 27450-27503). Road conditions may change often. For road conditions, call 559-565-3341 (press 1, 1). More »

  • You May Have Trouble Calling Us

    We are experiencing technical problems receiving incoming phone calls. We apologize for the inconvenience. Please send us an email to SEKI_Interpretation@nps.gov or check the "More" link for trip-planning information. More »

  • Vehicle Length Limits in Sequoia National Park (if Entering/Exiting Hwy 198)

    Planning to see the "Big Trees" in Sequoia National Park? If you enter/exit via Hwy. 198, please pay close attention to vehicle length advisories for your safety and the safety of others. More »

Ultraviolet Radiation

Since the 1970s, ozone high in the atmosphere has been decreasing. This allows more UV solar radiation to reach the earth's surface. The effects of increased UV radiation are not well understood. Several agencies and universities are studying links between UV radiation exposure and skin cancer and eye disorders in humans. UV radiation also has negative effects on plants and aquatic ecosystems.

UV radiation may also influence air quality in the parks. The smog obscuring park views is the result of chemical reactions that take place in the presence of sunlight. More UV radiation may speed up these chemical reactions and could increase the amount of smog and low-altitude ozone present.

In the mid-1990s Sequoia National Park was one of 14 national parks monitoring UV radiation as part of a UV network sponsored by the Environmental Protection Agency and the National Park Service. These measurements helped scientists better understand how changes in UV affect human health and various ecosystem processes. The network data are used for a variety of scientific studies including assessments of the effects of UV radiation on frog populations.

Ultraviolet Radiation Links
Environmental Protection Agency Ultraviolet Monitoring Program

Did You Know?

Cave formation.

The small gravity-defying cave formations found in Sequoia and Kings Canyon caves are known as helictites. They form due to the capillary action of acidic solutions and are composed of the minerals calcite and aragonite.