They are a generalization of the established system for rating ice described above. There is no consensus. However in the method which seems somewhat dominant in Colorado (home of the most desperate mixed climbs, probably due to lack of ice :-)) and championed by Jeff Lowe, the letter "M" is added to the technical grade. A "M5" is supposed to be as hard as a "5" in pure ice (the equivalence is obviously hard to establish) but involves dry-tooling and similar maneuvers. Sometimes, the grade is detailed into the pure ice part and the mixed part, ie Octopussy is "M8 WI5" since there are extreme dry-tooling moves to reach the free hanging stalactite, but once established on it the ice is not that hard. However, usually the latter part will be omitted since it is not the crux, leaving only "M8". The global rating could read something like an algebraic formula: "II M8 WI5 X" (X in my opinion: I think all the free-hanging stuff can easily collapse, as some climbers have experienced in the early 90s. I would be cautious with the current fad for this sort of climbing).
Another way to rate the mixed climbs is to give a rock-climbing rating for the rock moves. This method is preferred by the Canadians, who seem to be somewhat doubtful about all the M9 climbs :-). The problem here is that you have ice climbing gear, so usually the rating is not "absolute" but relative to how it feels with crampons, and therefore easier than a normal rock rating, but again there is no real consensus on this. (from Quang-Tau Luong)
Comments on the ice rating system (from Quang-Tau Luong)
对冰攀路线的批注
Although Albi Sole refers as grade 5 as the "5.9 of ice climbing", dont kid yourself. A grade 5 lead is a quite serious undertaking, more comparable in my opinion to a 5.10 trad lead. I am once of the only person that I know (:-)) who has been able to lead grade 6 ice while being only a 5.10- climber. You will see that grade 5 ice is actually rather difficult to find. For instance a guidebook like the one for Western Ontario or Western British Columbia has 140 pages, but lists only a handful of grade 5 climbs. There are no grade 6 at all in well established areas such as New England, Ontario, British Columbia (well, I must say was, until 1996, when The Theft was climbed in BC). This is because a grade 5 climb has to have about a half-pitch vertical, and a grade 6 a full pitch vertical, which brings me to the second point. Vertical is 90 degrees, not 85 degrees. This seemingly insignificant difference is actually quite important. When you are on 85 degrees ice you might have the feeling that it is overhanging, because of your position, but in fact there is not that many formations which are strictly vertical, except free-standing columns.
虽然 Albi Sole 的第五级相当于"冰攀的5.9级"，但是不要弄错了；第五级的先锋是相当艰难的任务，以我的看法不下于传统的5.10。我曾有一次是唯一一人攀岩能力只有5.10可以先锋第六级冰攀。你可以发现第五级冰攀路线很难找到；倒如像Western Ontario or Western British Columbia的guidebook有140页，但只有一些五级的路线；在开发完全的地方如新英格兰、安大略或不列颠哥伦比亚师妹有六级的路线。这是因为第五级大概有一半的绳距是垂直的，第六级是整个绳距垂直，会让我到第二个点。垂直是九十度而非八十五度，这似乎没什么的差别实际上是非常重要的，因为你的姿势的关系，当你在八十五度的冰壁上，你可能会觉得是在悬岩上，的除非是独立的圆柱。
There are only a handful of grade 7 pure ice climbs in the world, to the best of my knowledge:
就我所知，全世界只有少数第七级纯冰攀的路线，如下：
Riptide, and Gimme Shelter (Canadian Rockies) were the first established (mid 80s). Gimme Shelter is still unrepeated, because it has never reformed completly.
La Massue, and La Lyre, both at Fer de Cheval, (Northern Alps), both established the same day in Dec 1991.
Sea of Vapors (Canadian Rockies), winter 1993 (7+)
A part from those, there are a handful of one-pitch climbs which are mixed, and which have received a grade 7. T. Renault in France (Laventure, cest laventure next to Glacenost in Northern Alps, France) and J. Lowe in the US (Terriebel traverse, Seventh Tentacle, Octopussy 8??, in Vail CO) are the authors. While Thierry climbed "Laventure, cest laventure", the chunk of ice when he was standing collapsed, and he had to do a one-arm pull-up that he though he was not capable of. Jeffs climb are free-hanging stalactites which are reached through a dry traverse. Protected on the rock and with a preplaced screw from what I have heard. The second ascent party said that one climb was over-rated. The first grade 6 climbed in the world might have been Bridaveil Falls, Telluride, in the mid 70s. In the Alps, it was Les Viollins, although the first ascent, solo, by Chantriaux in 1982 is somewhat controversy.