Crasher and I plan to start grooming at 9:30 AM tomorrow. We will groom about 30 km of combi trails with both Pisten Bullies. We have a grooming manual that suggests we do not groom at temps below -20F and we see the temps above that at 9 AM. The grooming manual also states to groom with 2 machines in case of a breakdown. The manual further goes on to limit groom time to less than 3 hours at -10–20 F and not call in snowmobile, single track groomers at temps of -10 and colder.