Begin at the Upper Paradise Parking lot and follow the standard route until you reach Glacier Vista (6336 ft). From here cross the Nisqually 400 feet below you. Follow the path of least resistance across the glacier towards the Wilson Gully, which is a distinct low angle snow gully across the Nisqually. Once you reach the top of the gully you can follow the ridge line to the Wilson Glacier and the Turtle Snow field. My personal experience lead up through the Nisqually Ice Fall while making my way towards the Wilson Glacier. This was difficult but certainly more exciting. There are several options for gaining the Wilson Glacier. Follow the left (west) side of the Wilson Glacier until you reach a snow field (The Turtle) at about 9200 ft. on the Wapowety Cleaver.
The "climbing" starts at the upper most reaches of The Turtle snowfield. By now you should see the Kautz Ice Cliffs above. Camp Hazard is located at about 11,300 ft. From Camp Hazard, climb to the base of the Ice Cliffs and descend 200 feet down a gully between a rock cliff and the ice cliffs. Move left around the ice cliff base to the point that you can ascend the steep ice and snow chute known as the Kautz Ice Chutes. The climbing here may consist of 2 or 3 pitches of 50 to 60 degree snow and ice. Ice and snow protection are recommended as well as a second tool for this section. From the top of the chute follow the Kautz and Nisqually Glaciers to the south side of the summit crater. From Here you can ascend a short distance to the true summit Columbia Crest. You can descend you ascent route or do as we did and carry over and down the standard route. If you choose the later, make sure that all of your equipment goes to the summit with you.
Several other detailed descriptions have been suggested but are not included here. I leave the route description a bit vague because I feel that most of the fun in alpine climbing is finding the route on your own due in part to the fact that conditions change from year to year or even week to week.
Standard glacier travel and winter camping equipment. Ice screws, pickets and a second ice tool are useful in the ice chute.
I think it makes sense to warn about perhaps the most critical aspect of this route which is the significant objective hazard of icefall from the seracs of the Kautz Ice Cliff, especially in the descent gully from Camp Hazard. I was up there 2 days ago and was nearly killed by icefall myself. The danger can be somewhat lessened by leaving early in the morning and descending the chute AFTER the sun has begun to set (around 8 PM), but late evening icefalls do occur (there were three while we were there) and a huge one took place at midnight after we got back; we were camped half a mile down the Turtle and could feel the dust hitting our tent...the fall sounded like an earthquake. Addition thanks to russki82