After a difficult winter and an extremely wet spring, my pear trees suddenly started to die back.
Winter went to 25 below zero and spring brought standing water within 5' of my pear trees. They were in a more elevated area above the water. They seemed O.K. and started to leaf out normally immediately following about June lst. Now, they have almost completely dropped all their leaves with only a few left and suckers developing at the roots. One tree is totally without leaves and the other has only a few leaves at the very top of otherwise perfectly normal-looking trees. So, one is obviously dead to the suckers and the other has some suckers forming. Not sure what happened in the space of a month......too much water, not enough water (we have had regular rain up until last week), or winter damage?
Sometimes it just can't be explained; a tree death. You did however suggest some extreme weather that certainly likely played part in losing your tree.