Quaking aspens are sun-tolerant trees, members of the poplar family. In autumn, their leaves turn a golden-yellow, sometimes tinged with red. It is a short-lived tree and is often a pioneer in areas denuded by fire or other means. It provides shelter and water-retention, assisting in the establishment of young coniferous trees which eventually crowd out the aspens. (0.5 mile) 47 An EMERGENCY TELEPHONE is on the east side of the Park Road. (0.4 mile) 48 HOT ROCK is one of the many large boulders carried from the top of Lassen Peak. In the mudflow of May 19, 1915, these boulders were known to the local people as “hot rocks” because they retained their heat for several days. These which were buried in the mudflow material formed enough steam to cause funnel-shaped “eruption pits” in the mud overlying them. These pits can still be seen by careful searching in the upper portion of the Devastated Area. [Illustration: The Lassen Park Road is closed in winter beyond the skiing area at No. 3 in the Road Guide. —NPS photo by R. C. Milne] [Illustration: When the road is finally opened in early June, visitors drive through 20 ft. deep canyons of snow. —NPS photo by R. C. Milne] [Illustration: Brokeoff Mountain, described at No. 7 in the Road Guide, is part of the remnants of ancient Mt. Tehama. —NPS photo by R. C. Milne] [Illustration: A good place to photograph Lassen Peak at sunset is at Reflection Lake, No. 65 in the Road Guide. —NPS photo by R. C. Milne] The numerous log and boulder jams were built up behind obstacles as the mudflow began to lose its tremendous size and momentum. The new forest growth is partly obscuring this feature, and before long all traces of the devastation will be obscured. (0.4 mile) 49 LOST CREEK CROSSING. This stream has cut a trench not only through Lassen’s recent mudflow, but through earlier ones, some of which were separated by rather long periods of time. Upstream can be seen two lower layers of tree stumps, still erect and in place, laid bare by the erosive action of Lost Creek. This is also a good place to observe the activities of the water ouzels. The Nobles Trail parallels the road a short distance to the east. It was in use until completion of the main road through the park in 1934. (0.1 mile) 50 WEST BOUNDARY OF THE DEVASTATED AREA. The Great Hot Blast did not affect this area and only the effect of the mudflow of May 19, 1915, is visible. Recent growth of vegetation is healing the scars, but a change in soil, distribution of battered-down logs, barked tree trunks, and the change in the profile of the stream-cut bank across Lost Creek can still be seen.