What happened
During the landing flare and touchdown, the pilot had configured the aircraft to account for gusting winds. However, as the aircraft proceeded through the landing roll, a wind gust subsided, causing the airplane to depart the paved runway to the left side.
The terrain adjacent to the runway was wet and soggy. Upon departing the pavement, the airplane entered a ditch running parallel to the runway. The impact with the ditch caused the nose gear to collapse before the aircraft came to a complete stop.
Prior to the flight, the pilot had obtained weather briefings and was aware of the crosswind conditions present at the destination airport. At the time of the landing, a direct crosswind was blowing from the left with sustained winds between 10 and 15 knots, gusting to 20 or 25 knots.