Along with Gibralter Ledges, the Ingraham Glacier Direct is the standard route on Mount Rainier during the winter (December to the end of May). The route is quite a bit easier than Gibralter Ledges and is more direct than the Disappointment Cleaver. Most winter ascents, including those from RMI's Winter Mountaineering Cource, utilize this route. The line up through the crevasses changes each year, so make sure you ask a ranger about any current info.
Start at Paradise at 5,500 feet. Hike up to Camp Muir using the trail up to the base of the Muir Snowfield, then up the snowfield. Most teams either use the Muir Hut to spend the night or camp in the area around the hut or at Ingraham Flats.
From Camp Muir at 10,080 feet, head over to Cathedral Cap or use the steeper but shorter Cadever Gap to access the Ingraham Glacier. Make sure you are roped up while on the Ingraham. Hike up the the flat spot at 11,100 feet that is called Ingraham Flats. From here you will be able to see the Disappointment Cleaver route to the East.
The route heads directly up the 45 degree headwall of the Ingraham Glacier avoiding many small and some huge crevasses. The stomped out route usually follows a switchback pattern, lowering the climbing slope to about 35 to 40 degrees. You will notice some huge seracs towards the west side of the Ingraham Glacier at about 12,500 feet. The route avoids these by cutting up to the east above the Disappointment Cleaver. The crevasses that you pass over at about 13,000 feet are incredibly huge. It makes you want to just stare in amazement.
The upper portion of the climb involves some low angle switchbacks until the summit rim is obtained at 14,100 feet. This section is more about perserverence in the lower oxegen high altitude air. From the crater rim, it is a 20 - 30 minute walk over to Columbia Crest at 14,411 feet.
Descend the same route.
Most ascents are done from January to the end of May under winter like conditions. Here is a full list of recommended gear for a climb during these months.
Double plastic boots
Synthetic liner socks
Heavy wool socks
Long underwear bottoms
Fleece pants (optional)
Down parka with hood
Polar fleece hat
Means of self rescue (ie. 2 prusicks or 1 prusick and 1 ascender, etc.)
Pickets to set an anchor
Webbing and Cordalette