According to the AP:
The missing group includes four clients of Seattle-based Alpine Ascents International and two guides. They were due to return from the mountain on Friday. When they did not return, the climbing company notified park officials, Park Ranger Fawn Bauer said.
There was a small change in weather on Wednesday that brought flurries and hail to the mountain.
The search for the missing climbers is focusing on the Liberty Ridge area, near from where they were last heard from, Bauer said. The search includes climber ranger teams on the ground and flyovers with a helicopter.
A spokesperson for Alpine Ascents, Gordon Janow, has not released any information or names of the climbers, stating "Let's hope they're found and that it goes well."