MAMMOTH, Wyo. -

Plow crews in Yellowstone National Park are getting close reaching one of the park's high-elevation passes. The process of clearing the roads takes months, and we're told snowplows are about three-quarters of the way done for the season.

Monday morning our journey into the park started at Mammoth. We met with Dan Hottle of the Yellowstone National Park service as he mapped out our day.

We wanted to take a closer look and ride along with plow crews to see how just over a dozen equipment operators tackle more than 300 miles of paved roads in the park. We went beyond the "road closed" gate, which is near Canyon Village. Even after the gate, the roads were clear with snow piled high on each side.

About 30 miles later, we reached the plows on East Entrance Road, just a few miles before they reached Sylvan Pass.

Marty Powell has 22 years under his belt as an equipment operator. "Once we get to the pass, it will slow down, it will take us a day or so to get through Sylvan Pass," said Powell.

We hopped in Powell's snowplow as he led the way. While the plow was only moving one mile per hour, the blades in the front of the plow can remove 2,500 tons of snow per hour.

"It's pretty fast; you don't want to get in the way of it," said Powell.

In another corner of the park, more plows also slowly chipped away at the deep snow drifts. We headed that way next, and caught up with the plows about 50 miles away on South Entrance Road near the Lewis River.

We were told crews here were running tight on time, Hottle tells us they have to stick to a tight schedule as they work toward their deadline.

"Our real big season starts around Memorial Day weekend, that is when the RVs will start one at a time, two at a time," said Hottle.

It is a monumental task to clear the roads, but Hottle says he's confident the crews will get the job done as they do every year. As they near the finish line, visitors are already lining the roads and enjoying the beauty of the park.

According to park officials, the overall annual cost of preparing the park for Spring opening is $1 million. Much of that cost is made up by fuel for the snow plows. The park says on any given day, those plows can guzzle anywhere from 1,300 to 2,000 gallons of diesel fuel.