To boost sales, Aspen Mountain began allowing snowboards in 2001; now 10 percent of visitors there come to snowboard. Keystone in Colorado, Park City Mountain Resort in Utah and California's Alpine Meadows began admitting snowboarders more than 10 years ago; now 30 percent of visitors to Alpine Meadows are snowboarders.

The nation's remaining three public resorts that ban snowboarders haven't ruled out a change of heart. Deer Valley says an overwhelming majority of guests still prefer the ski-only experience but it re-evaluates the issue every year. Mad River Glen says it would take a two-thirds vote of the co-op's shareholders to change its ban. Alta says the snowboard ban is a business decision.

With a ski-only policy, "you're not just losing the snowboarder. You're losing the family or in some cases the whole ski club," says Gordon Briner, general manager of Taos Ski Valley. His answer to local real estate investors' complaints is that "in every community that's adopted snowboarding, the real estate values go up significantly."

Dianne Robbins says she plans to put her Taos ski home on the market at the end of the season because of the policy change. She and her husband, Larry, who owns a Pensacola, Fla., swimming-pool company, bought a 10,000-square-foot chalet in 2005 for slightly more than $1 million, with an indoor pool, steam room, sauna and a two-minute walk through the woods to the lifts. The Robbinses invested $1 million more in remodeling, a project Dianne Robbin says they won't continue.

"The whole reason for buying and investing there was the no-snowboarding policy," she says. Snowboarders, she says, "are careless a little bit." She fears they will shorten the season by pushing snow off the resort's signature steep slopes. "There comes a point when if it's scraped away, it's definitely not coming back," she says.

Alejandro Blake, events coordinator and a grandson of Ernie Blake, the resort's founder, says Taos Ski Valley has been weighing the change for seven years. Skiing clans who came to Taos for generations began writing letters to say they couldn't return because a child or a grandchild wanted to snowboard.

Four years ago, the Blakes asked resort guests to rate the importance of the no-snowboards rule in their decision to visit, on a scale of one to five. For the past two years, more than half the respondents gave it a one, two or three — indicating dwindling support. "It is a business at the end of the day," says Alejandro Blake. "We weren't forced into this, but we needed to do it in order to grow."

He says the decision to eventually accommodate snowboarders was made two years ago, when the resort finalized plans for a major expansion of the base area. The resort decided to enlarge rental shops to handle snowboards, install snowboard-size racks outside and build more hotel rooms to house an expected 10 percent to 15 percent increase in visitors.