As a reminder most park agencies, including Chino Hills State Park and the Puente Hills Habitat Preservation Authority, close the trail systems during and after rains to preserve the integrity of the trails. The Puente-Chino Hills are known for clay soils, which are sticky and take longer to dry out. Trail users try to avoid the puddles, which expands the trail unnaturally and impacts the land. The standard rule is for every quarter inch of rain the trails are closed for 48 hours.