We're short on "Updated Route Information." The cool new information is that a team summitted via the Tahoma Glacier during the last week of March. For more information, check this out.
If you would like to attempt the summit during this off season, you'll have to start at a park boundary. Keep in mind that all of the roads into the park are closed to vehicular traffic. Starting a climb at a park boundary will add a number of miles to your trip. Plan for an extended stay: bring extra food, fuel, and supplies.
For routes on the south and west side of the park (i.e. access via Paradise or Westside Road) you will need to register in person at the Nisqually Entrance Ranger Station. If you're serious about climbing the mountain, I welcome you to email me with registration, route conditions and other climbing related questions.