N/A Airport
Aircraft Accident/Incident Report

Boulder, Colorado 80301
Saturday, June 8, 2013 8:54 MDT

The pilot reported that he checked the weather forecast before takeoff and received a briefing from flight service. He and the other balloon pilots flying that day compared the weather information and determined that the weather was good enough to fly. About 45 minutes into the flight, at 3,000 feet above ground level, the pilot noticed that the other balloons flying nearby were "screaming up and down" and that, within 5 minutes, the wind, which had been carrying them easterly at 6 to 8 knots, shifted to the southwest at 30 knots or more. The balloon was getting bounced around, and the wind was not subsiding, so the pilot decided to immediately land the balloon. The pilot briefed the passengers for a high-wind landing and landed the balloon in a conservation area. The basket tipped over and was dragged for about 50 to 60 yards until a wind gust lifted the balloon about 5 feet above the ground. The pilot pulled in the top vent, which put the balloon back on the ground, and it finally stopped moving. A review of meteorological data available at the time of the preflight briefing indicated, in part, that wind from the west existed at 10 knots or less before takeoff. The National Weather Service (NWS) terminal area forecast expected easterly wind shifting to the northwest during the anticipated flight at 13 knots with wind from the north gusting to 23 knots after 1000 mountain daylight time. The NWS area forecast did not expect any high winds across Colorado. The NWS Aviation Forecast Center had no advisories current for low-level turbulence or high winds over Colorado surrounding the anticipated flight. However, shortly after takeoff a sudden increase in windspeed occurred across the region with wind gusts from 20 to 38 knots. The NWS misjudged the timing and underestimated the magnitude of the frontal boundary moving across the region. It is likely that, if the pilot had known about the gusting wind at the time of takeoff, he may not have chosen to fly that day.

The balloon's encounter with unforecast strong gusting wind, which resulted in a high-wind landing. Contributing to the accident was the National Weather Service's misjudgment of the timing and underestimation of the magnitude of the frontal boundary moving across the region.