To get to the base, Kalte Mürz Walley, turn to the right 1.5 km after Frein an der Mürz on the first crossing, driving in the direction Mariazell. (See the main page for how to get to Frein.) The crossing also bears a marking "Gasthof Leitner". Drive to the end of the permitted road.
The non-marked route starts south of the parking place, first for 200m on a forest road, then turns left to north and goes right of a big forest aisle. After some 200 hm a forest road is crossed, the ascend continues over it through the forest. Above the trees boundary, head slightly left to the peak of Hohes Waxeneck. Ski down to the saddle south of it and ascent to Donnerwand over its ridge.
In the combination with Donnerwand and downhills as described here, approximately 1500 hm and very impressive. More variants possible.
Ski, avalanche gear.
From Donnerwand: go back on the ridge, until a broad gully goes down to north. Follow the gully down to a big forest aisle, turn to the left to a small hut. Ascent from here to Hohes Waxeneck. Again, look out for possible cornices and avalanche danger.
From Waxeneck, either ski down the ascend route, or head slightly to the left and after 100 hm a somewhat narrow, steep nice gully is entered.
December to March, powder snow preferred. The ascent to Waxeneck is relatively safe even after snowfalls, but look out for avalanche danger near the ridge on both sides.