You must have been Hammering
You must have been Hammering the accelerator pedal, because I made the EXACT same drive and used less than 30 miles of range on the same section! Sure you will burn range as you drive uphill, just like you burn more gas when driving up!! I averaged 4 miles of range /mile driven uphill....but then gained most back coming back down.
How much range did you use coming DOWN the mountain??