SAN DIEGO -- San Diego County officials are warning residents to take extra precautions against the heat this weekend as temperatures soar into the triple digits, especially when hiking on popular waterfall trails in the Cleveland National Forest.
A National Weather Service excessive heat warning for the deserts took effect at 11 a.m. Friday and extends until 9 p.m. Wednesday.
A less severe heat advisory has been issued for the inland cities of Escondido, San Marcos, Poway, La Mesa, El Cajon and Santee. That advisory will take effect 11 a.m. Monday and continue until 9 p.m. Wednesday, with the weather service predicting high temperatures in those inland valley cities of 95 to 101 degrees on Monday and 96 to 103 degrees Tuesday and Wednesday.
A similar heat advisory in the mountain areas with elevations lower than 5,000 feet, which includes Julian and Pine Valley, will be in effect from 11 a.m. Saturday to 9 p.m. Wednesday. High temperatures in those areas are predicted to reach 92 to 102 degrees over the weekend and 96 to 104 degrees Monday through Wednesday.
But the hottest weather is expected in the deserts, where high temperatures were predicted to reach 107 to 112 degrees Saturday and rise to 109 to 114 degrees Saturday, 111 to 116 degrees Sunday, 113 to 118 degrees Monday, 115 to 120 degrees Tuesday and 114 to 119 degrees Wednesday.
"With high temperatures expected ... county health officials are reminding the public to ... pay extra attention to children, elderly and pets," county spokesman Tom Christensen said.
Temperatures along the coast and in the western valleys will be somewhat cooler, but still 5 to 10 degrees above average, according to the weather service.
Meanwhile, authorities from the San Diego County Sheriff's Department and Cleveland National Forest are warning hikers to use extreme caution while hiking at Three Sisters Falls and Cedar Creek Falls, a pair of popular water hikes made more appealing during hot weather.
"With extremely steep slopes (and) a rugged and eroding trail, the (Three Sisters Falls) hike is listed as strenuous to extreme, and is suggested for those in good physical condition," sheriff's department spokesman Ryan Keim said. "Couple this with extreme summer heat, no shade and rocky, unstable terrain, and many hikers quickly find themselves overwhelmed and under prepared."
The 6.6-mile hike to Cedar Creek Falls in Ramona is considered moderate to strenuous, provides no shade and is completely uphill on the way out, Keim said.
Sheriff's Search and Rescue volunteers and deputies in the sheriff's ASTREA helicopters have this year already responded to 24 incidents of distressed hikers at Three Sisters Falls and Cedar Creek Falls. In 2016, rescuers responded to 51 calls to those areas.
Hikers and others planning to go outdoors are advised to stay in groups, keep hydrated, dress for the heat in light and breathable clothing, take regular breaks and stay indoors if the heat becomes overwhelming. County officials also advised residents to stay in air conditioning during the hottest hours of the day, take cool showers, avoid using the oven to cook and avoid unnecessary sun exposure.
The hot weather will increase the risk of heat-related illness and anyone working or spending time outdoors would be more susceptible, as will senior citizens, children and those unaccustomed to the heat.
Forecasters advised residents to reschedule strenuous activities to early morning or evening and authorities also warned against leaving children or pets in parked cars, which can heat up to lethal levels in just minutes.