Tune into any business-oriented programme and someone will likely be talking about a building slowdown around North America. That's true many places, but definitely not at any of the ski areas we've been visiting.

Expansion is rushing ahead at jet speed, not only expanding slopes, adding lifts and enhancing accommodations, but building ever more private high-priced residences affiliated with them.

They're also enlarging all the other winter sports segments of their properties. Everything from snowmobiling, ice skating, snowboarding, sledding, tubing and dogsledding.

They realise their snowy mountain scenery attracts a wide diversity of interests. And that includes those who come with the sole purpose of lodge-lounging, enjoying snowscapes from picture windows near the fireplace and savouring many dining options.

Leafing through all the current updates in my mail, the expenditures are often mind-boggling. As Illinois Senator Everett Dirksen once commented: "A million here, a million there . . . first thing you know you're talking real money."

That was more than 20 years ago and these days it often reaches into billions.

It's doubtful any area is spending more than Northstar-at-Tahoe. East West Developers built ¿ and some conservation-minded purists might say overbuilt ¿ Vail, Beaver Creek, Hilton Head, Sea Pines, South Carolina; Summit, Colorado, and are working at Deer Valle, Utah.

They're now concentrating on this pristine area north of Lake Tahoe. We'd heard some conservationists lamenting what one called a "massacre" of 150-year-old ponderosa pines and drove up from nearby Tahoe Vista to see for ourselves. Last time there it had been a very small development.

Probably the biggest expansion and development of any ski-oriented property in North America is occurring here. A large new terraced car park to accommodate the volume of skiers expected to park here and be shuttled up to the new lifts was the first thing we encountered.

A maze of winding roads led past wooded mountain-side subdivisions. Many large multi-million-dollar homes already existed among the trees, with a multitude of others under construction.

With the California fires raging at the time of our late October visit, it was easy to understand how flames raced through these thickly forested resident areas.

Although there seems to be major building going on everywhere at Northstar enlarging smaller resort properties, it's the summit where the most massive and dramatic development is in progress. What looks to be only slightly smaller than the Banff Springs Hotel or Manor Richelieu is in progress, with masses of construction vehicles passing us on the mountain.

A large new gondola has been installed and the property is being heavily promoted as an emerging year-round vacation spot, with hiking and horseback riding trails. At present, there are 16 lifts, 77 trails on nearly 2,500 acres. Check www.Northstar At Tahoe.com.

Northstar is only one of a sizeable collection of ski slopes in the Lake Tahoe area, a reason why the region is promoted as a place one can take a "ski safari", sampling a wide variety of different areas.

Probably most well-known of them all is Squaw Valley, site of the 1960 Winter Olympics. Just off Rt. 89 between Truckee and Tahoe City, it's easily accessible.

You'll notice it immediately with traditional Olympic symbols at its entrance. It's noted for many things. One is its advanced lift system ¿ in fact, it's the only ski slope with a Funitel cable car and K22 high-speed quad.

And although it has runs for all levels of skiers, its steepest, most challenging ones are a special lure for the most advanced experts as well. Sarah Ferguson worked there at the children's ski school in the 1980s before she became Duchess of York.

It has 34 lifts, 100-plus runs on 4,000 acres. Special back-country tours led by experienced guides were new there this season. So were moonlit snowshoe tours around its upper peaks for great mountain and lake views.

And having just been there during full moon, viewing it over the vast mountain rimmed lake, the world's 12th largest, can only be described as spectacular. We'll try to plan next year's visit to coincide with full moon.

Just down the road is Alpine Meadows, a quieter retreat which offers 13 lifts, more than 100 trails on 2,400 acres. Their proximity to each other shows Travel Agent magazine was very much on track when it described the area as a place where you can ski a different slope almost daily.

Continuing south, Heavenly likes to call itself a sort of skiers' Las Vegas. Its location edging the California-Nevada state line offers access to major casinos and night clubs in operation around the clock.

Located at Lake Tahoe's highest elevation, slopes offer distracting views out over a dazzling landscape. Advertisements proclaim "possibly the best tree skiing on the planet". Unfortunately, Sonny Bono met an untimely death there.

We've found its mountain-top trails are also interesting to follow in summer when vacationers can ride a lift up to the restaurant, dine on its terrace, then take to the trail.

Considerable building was going on here . . . a 50,000-square-foot convention centre, 16,000-square-foot Rock Resort Spa and two luxury condo hotels, along with shops and restaurants are expected to be finished in the winter of 2009, operated by a Vail Resorts subsidiary (East-West Partners). New this year was Heavenly Sky Flyer at Adventure Peak. This elevated zip-line cable ride sends brave adventurers off on a 50-mph ride with a vertical drop of more than 500 feet. It's the longest zip line in lower US at 3,100 feet.

Heavenly offers 30 lifts, 91 trails on 4,800 acres. Check www.heavenly.com. Family-friendly Diamond Peak ski resort at Incline Village attracts locals with six lifts, 31 trails on 655 acres.

Check www.diamondpeak.com.

The list is long. There's Sierra-at-Tahoe which is proud of its "vertical excitement" with plenty of steep backcountry skiing. Check www.sierraattahoe.com.

Up across Donner Pass is Sugar Bowl, originally built by Disney in 1939. View it at sugarbowl.com. It has 13 lifts, 84 trails and 1,500 acres with new ski-in condos.

Halfway over Route 431, the mountain road between Reno and Lake Tahoe, is Mt. Rose. A ski shuttle there from Reno runs from late December to late March. Family-oriented, it features everything from rookie runs to intermediate and advanced. There's also a regular shuttle to Lake Tahoe.

Both snowboarding and cross-country are very much part of the local scene. Although available at almost all mentioned properties, some areas specialise in them.

Tahoe Donner Cross Country northwest of Truckee has 49 trails on 4,800 acres. Some are for beginners, intermediates, advanced, expert and wilderness and there are two snowshoe trails. There are five warming huts with a day lodge at an elevation of 6,600 feet.

Rental equipment is available. Check www.tdxc.com. It also has a downhill area.

Royal Gorge Cross Country Ski Resort at Soda Springs is considered the largest in North America and ranked number one by Snow Country magazine. With more than 9,000 acres, it has 90 trails. Check www.royalgorge.com.

Did you know this region receives as much as 480 inches of snow annually? There have been some times when it has accumulated so rapidly, snow ploughs were overwhelmed. Skiers trying to get there couldn't and those there couldn't get out.

Taking ski-train trips in college, I used to think being stranded snowbound at one of those ski resorts would be very exciting. It never happened, but they were always certainly exciting and great fun anyway!

Next week: The best and worst of 2007