Crunch Time for FedEx and UPS as Last-Minute Holiday Shipping Ramps Up

Donner Pass, the icy stretch of road that cuts through the Sierra Nevada mountains, is 2,000 miles away from FedEx’s world hub in Memphis.

But as the holiday delivery season hits its peak, dispatchers here are keeping an eagle eye on weather conditions along the pass: Any trouble could make it impenetrable for the carrier’s trucks, closing a crucial route out of California.

This year, FedEx says it has strengthened its contingency planning, after shippers were summarily slammed for delivery delays last holiday season. Those contingency plans sprang into action...