Training without snow

Living in the Seattle area, I have to drive an hour or more to get to the snow. This means that even during the season I will be training on snow only once or twice per week. How do you get fast without snow? A recent article on Fasterskier says you need specificity which essentially means "You have to rollerski". This is another vote confirming my acquisition of rollerskis... especially since I get only limited snow time even during the season.