At approximately 10:19 MDT, a Beech V35A crashed into mountains during cruise flight and the pilot is presumed dead. The aircraft departed Lees Summit, Mo. at approximately 06:00 CST and was en route to Kremmling, Colo. IMC prevailed but no flight plan was filed. The pilot was instructed by Denver Approach to contact Denver Center but failed to do so. The aircraft was located along the north face of Arapaho Peak at about 14:30 the following afternoon. The aircraft impacted mountainous terrain at an elevation of 12,500 feet. A witness said he heard a plane flying overhead traveling low to the ground. He looked up but was unable to see the aircraft due to the low cloud layer. He stated that at the time he heard the airplane flying overhead, a squall line approximately 3 miles wide was passing through the area, and the mountains to the west were obscured.