I don't reach the 100,000 mile mark before 5 years. Is the pink mopar HOAT coolant done after 5 years? I changed it initially around 5 years and like 83,000 miles. I'm at 10 years and 123,000 now.
IMO it is best to treat the coolant life expectancy claims like the manufacturers treat their new car warranties - xx miles/x years, whichever comes first.
So if the coolant sees its 5th birthday before it sees its 100,000th mile, change it.
Allowing it to go beyond 5 years in order to reach the 100K mile mark is a recipe for disaster IMO, especially considering the severe operating environment your geographical location imposes.
(My position on this subject was recently bolstered by personal experience with factory fill Mopar HOAT coolant that was allowed to go beyond the 5 year mark even though it had not yet been in service 100K miles. There were clumps of brown goo left behind in the overflow tank and what looked like sand particles filtered out of the drained coolant when transferring from drain pan to collection jug.)