Abplanalp is the surname of a family originating on a mountain named Planalp above Brienz, a village in the Swiss Alps near the town of Interlaken, attested in August 1306 and probably dating to the late 10th century when an avalanche occurred on the mountain. The name has frequently been changed to Planalp in the United States.
References
Abplanalp Wikipedia(Text) CC BY-SA