At around 9:40 AM they encounter more weather -- as in seriously heavy fog -- and the chopper turned south. This was critical, because they turned toward a mountainous area. The pilot suddenly and rapidly climbed from about 1200 feet up to 2000 feet. However, moments later -- around 9:45 AM -- they flew into a mountain at 1700 feet. Flight tracker data shows they were flying at about 161 knots.