The Claremont Hills Wilderness Park (CHWP) is located at the base of the San Gabriel Mountains and is a popular hiking spot for residents and visitors from across the region. Each year, tens of thousands of visitors enjoy the park’s trails, wildlife, and vistas.
The Wilderness Park is open daily; however, it can be closed for a variety of weather advisories, park maintenance, or emergencies, and may be extended to avoid personal injury or loss of life and property.
In May 2016, the City Council approved the policy to authorize automatic closure of the CHWP during red flag conditions as a pre-emptive safety measure to protect life and property. Alerts are monitored through the National Weather Service. In addition to closures during Red Flag Warnings, the City Manager can authorize for temporary closures including fire, heat, heavy rain, winter storm, flooding, thunderstorms, high winds, earthquake, road and trail maintenance, and requests by law enforcement, as well as any other disasters impacting the CHWP. Closures may remain in place as needed to protect visitors from rockslides, unstable trees, high water, and smoldering fire activity. In order for the CHWP to re-open, emergency vehicles must be able to access the fire roads at all times.
Park closures are well publicized through multiple media channels including Constant Contact, Facebook, Instagram, Twitter, City Manager Weekly Update, and the City Website, and include the estimated duration of the closure.
Reasons for closure of the Claremont Hills Wilderness Park include:
Red Flag Warning
A Red Flag Warning is a forecast warning issued by the United States National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wild land fire ignition and rapid propagation. With drought conditions, very low humidity levels, high or erratic winds, which may include lightning, the Red Flag Warning becomes a critical statement for firefighting agencies. To the public, a Red Flag Warning means high fire danger with increased probability of a quickly spreading vegetation fire in the area within 24 hours. The current policy approved by the Claremont City Council calls for the CHWP to automatically close when the National Weather Service issues a Red Flag Warning that impacts parcels of the CHWP.
Fire
Fires can occur quickly and without warning. The CHWP will close if there is a fire within 10 miles north, northeast, or northwest of the park. The park will remain closed for 24-hours or as needed following a fire that has happened in the park or within five miles of park boundaries.
Heat
During Heat Advisories, the CHWP may be closed or may close early and remain closed for the duration of the day depending on the severity of the heat. There are two levels of heat advisories:
- A Heat Advisory is when the maximum heat index temperature is expected to be 100° or higher for at least 2 days, and nighttime air temperatures will not drop below 75°.
- An Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. This warning is when the maximum heat index temperature is expected to be 105° or higher for at least 2 consecutive days and nighttime air temperatures will not drop below 75°. Excessive heat outlooks are issued when the potential exists for an excessive heat event in the next 3-7 consecutive days.
Heavy Rain, Winter Warnings, & Flooding
Winter Storm Warnings are issued for a significant winter weather event including heavy rain, snow, ice, sleet or blowing snow or a combination of these hazards. The CHWP will be closed if two or more inches of rain are expected within a 24-hour period or heavy rain (two to four inches) for more than three consecutive days. Flooding may also occur within the park due to extended rain or heavy rain fall.
Thunderstorms
A Severe Thunderstorm Warning is issued when severe thunderstorms are happening or are imminent in the warning area. Severe thunderstorms have wind of 58 mph or higher and/or hail one inch or larger. Wind this strong is able to break off large branches, knock over trees, or cause structural damage to trees. Some severe thunderstorms can produce hail larger than softballs or winds over 100 mph. Thunderstorms also produce tornadoes and dangerous lightning; heavy rain can cause flash flooding. Warnings indicate imminent danger to life and property.
High Winds
A High Wind Warning is defined by sustained strong winds with even stronger gusts. A Dust Storm Warning is issued when visibility is 1/2 mile or less due to blowing dust or sand, and wind speeds of 30 mph or more.
Earthquake
The CHWP will be evaluated by Claremont Park Rangers and emergency personnel after an earthquake to evaluate downed trees and debris that may be blocking the roads. Once adequate vehicle access has been established, the City of Claremont will determine any required maintenance and will reopen the park once the roads have been cleared, and the trails are safe for park users.
Road & Trail Maintenance
Due to extreme weather, natural disasters, or annual road clearance/maintenance, the CHWP may be closed for repair. Once road conditions have been established safe for vehicles and crews to access the damaged areas, the road repair or maintenance will be conducted quickly. The public will be notified of the anticipated timeline for the park closure. Once the road work or trail maintenance is completed and deemed safe for reopening, additional notification will be distributed through City media sources.