Here's something to support your thought:

The main factor influencing elk mortality turns out to be severe weather. (Journal of Wildlife Management, Vol 65). In 1997 when the elk were weakened by an unusually harsh winter, wolves killed 26% of those they tried to catch. The following year, when the weather was milder the elk were healthier and the wolves' success rate dropped to 15%. Recent mild weather has allowed the elk population to increase, even know the wolf population has also grown (Levy, S New Scientist, issue 2367). Elk are undoubtedly the wolves' primary prey, but are unlikely to be eaten unless the elk are too sick, hungry, old or young to defend themselves. It has been found that healthy elk are very good at protecting themselves against wolves. In fact, several wolves in the park have died of wounds inflicted by slashing elk hooves or antlers. (Levy, S New Scientist, issue 2367)