The TC soldiered on up the North Slope, where it was even colder. By this time I was shivering uncontrollably and then we got a puncture, rear offside. Again. What a place to have to change a wheel. It was a real flat so getting the jack underneath was an issue – the permafrost was a couple of inches below the surface. I looked around for flat stones to prop up the car and removed the spare wheel ready to fit, Bob struggled with the jack. I put the flat tyre on the spare wheel carrier. It was imperative we both kept moving and made a fast wheel change. This was late summer for heavens sake, what the hell is it like in winter? Trucks and pickups passed us by without even slowing down.

We didn’t have a hot drink, only freezing cold water and very cold sandwiches to eat. Tundra under snow is spectacular and frightening – true wilderness. On the way up we had passed a herd of musk oxen; on this drive back we found them again, this time bunkered down low and huddled together in small groups for warmth. We climbed the Atigun pass over the Brookes range and descended towards Wiseman, the snow gradually disappearing and the sun came out to shine. By this stage we could hardly get out of the car. I went straight under a red hot shower and cranked the cabin heating up to full but couldn’t warm up. Umpteen cups of hot tea, hot soup and hot food didn’t stop my shivering. All I wanted to do was hibernate. Maybe I had been a squirrel in some past life.

We wondered how the motorcyclists managed. There were many doing the Dalton highway, stopping frequently to clean their visors and jump up and down to warm up. We learned later that some of them have plug-in leathers that warm up from the bike electrical system, which sounds a bit kinky. We also learned that the same day we left Prudhoe Bay some young people on the oilfields bus tour had taken a dip in the Beaufort Sea. We thought we were crazy. The next day back to Fairbanks was easy but filthy, first of all stopping at Coldfoot to repair the puncture. I was still shivering.

We headed back to the tyre place to find out exactly what the problem was with the tyres. This time the guy found a tiny nail in the tread, patched the tube and off we set to do some shopping. We came back to the TC and another flat. Back to the tyre place, patched again, put the tyre back on, this time tested it in a huge tank of water and hey presto, bubbles. We lost count of the number of times the tube came on and off, and we ended up using our last spare tube in desperation. The guy was happy with the tyre this time. We headed south for Denali National park to do some serious animal watching.

We planned on overnighting at Healy just outside Denali. I was still shivering. Bob was really worried by this time, fished out the thermometer and sure enough, I was running a fever. Straight off to the nearest medical centre and an hour later and after a process of elimination we divined it wasn’t hyperthermia, pneumonia, rheumatic fever or malaria, but it could have been any number of other fevers. Tender kidneys pointed to a kidney infection, take these antibiotics, give us some bodily fluids and move to good medical facilities and await the results. Off we went to Anchorage and bunkered down for three days just to stay warm. The tyre continued to deflate slowly. Bob took the tyre off, fitted a new tube and put the tyre back on manually and guess what, no more punctures. Ah, the old pinched tube trick had caught us out. Each time the tyre repair place had fixed one puncture they had caused another. Feeling heaps better we set off south to the Kenai peninsular and ended up at Seward. We were disappointed to have to miss Denali, but the weather was best described as filthy and we wouldn’t have been able to see a thing anyway. The Kenai made up for all that.

Seward is a fantastic spot, Resurrection Bay is astonishingly beautiful. This whole seaboard was covered in oil when the Exxon Valdiz oil tanker went down. 250,000 seabirds died in this area alone. We could not visualize the devastating impact this would have made at the time, and what a cruel irony that one of the most beautiful parts of the world should be trashed by such a disaster. Severe winter storms broke up the oil slick and dispersed it into great globs of filth, which is not to say that it disappeared, far from it. After rough weather, patches of the stuff reappear on beaches, constant reminders of the past.

Our drive to Homer at the end of the Kenai, in glorious sunshine, took us past the most westerly road in Alaska, and past the old coastal settlement of Ninilchik. What a place. It was my birthday, so we usually do something energetic (no, not that) just to prove we still can so we walked out on the Homer Spit to a fish restaurant right on the end of the promontory. What views - a panorama of snow clad mountains across Cook Inlet and over to the north, a smoking volcano. Volcanoes and thermal activity have been a recurring theme right from the very beginning or our trip in Chile. Basically we have driven the full length of the Pacific Ring of Fire from far south to far north, past active and sleeping volcanoes, hot springs, geysers, mud pools and fumaroles. Our path through Ecuador had been blocked by an erupting volcano; Volcan Chaiten in Chile had erupted with hardly any warning, causing the evacuation of towns we had driven through on the Camino Austral; earthquakes have happened in Peru. There is no such thing as a dead volcano, proved by one such along the Avenue of Volcanoes in Ecuador going up since we were there.

Scientists worry about pandemics – there is a pretty serious one going on as I write in the USA and Canada which causes perfectly sensible people to take up fishing en masse. These poor people can spend all day and all night sometimes pulling in fish bigger than themselves. They even have photographs taken standing next to their trophies so that they can say to their peers – "look, I survived salmonitis" or "I came through halibuteria unscathed". The worst case we saw was an elderly gentleman standing waist deep in freezing river water throwing a line about, casting we think they call it, just to satisfy this craving to catch a fish. Like the grizzlies that stalk the rivers at this time of year to fatten up on salmon returning to their spawning grounds, we have a photo of a row of these poor people forming a human chain across a cold river, basically doing the same thing as a group of grizzlies – satisfying their craving for salmon. There is no known antidote. If you catch it, you just have to rely on your own immune system. Some people take this disease to the grave.

Taxidermy is something that used to happen years ago in Europe and the UK, leading to mangy looking furry things slowly decaying in glass domes in "olde worldey" pubs with low ceilings and threadbare carpets. Taxidermy in North America is a thriving business. Most hotels in this neck of the woods sport at least a stuffed grizzly bear, usually alongside moose, elk and muledeer heads poking out of walls and sporting huge headgear. Yellow Pages carry a list of taxidermists in most locations. Antlers adorn most small scale retail outlets, garages and information centres. You are left in no doubt that you are in wilderness - big country that cannot be tamed. Humans are just another species that just happen to live here.

It was time to turn the ship around and retrace our route back through Alaska to Tok, and back through the Yukon and into British Colombia. We returned to the same motel in Whitehorse. A chap came towards us at a brisk pace. He found out that we had been here a few weeks previously and thought he had missed us, but was delighted that we had come back. He had a business premises just next door to the motel where he kept his MG TF 1500. Would we like to come around that evening for coffee and cake?

We spent a really great evening with him and his partner, where we learned all about motoring in "40 Below". This is a term we had heard a lot, which means either 40F below freezing, or 40C below freezing, the only temperature where the figure is the same in Fahrenheit and centigrade. Pistons freeze and shrink, so that when you start an engine in the morning, the engine sounds like a load of tin cans being rattled, gear changes are a challenge and tyres literally form a square where they have been stood overnight. It sounds funny but I bet vehicles don’t last long in these conditions. We had noticed electrical plugs in parking areas outside hotels and motels. This is where guests plug in engine warming devices to avoid cold damage to moving parts.

Watsons Lake is not my most favourite spot in the world. Accommodation costs are astronomical and facilities poor. Everyone entering or leaving Alaska has to pass through here, you are a captive audience and you are left in no doubt. We now have another reason for not liking the place. About an hour out of Watsons Lake, we broke another half shaft. We carry two spare shafts pressed onto hubs, one left hand and one right hand. We had already used up our spare left hand hub and shaft after crossing the Hoover Dam way back in Arizona. Guess which shaft had broken this time? Correct, the left hand again. Bob hitched a lift back to find someone with a hydraulic press to remove the right hand hub and press the left hand hub onto the one remaining spare half shaft. He was gone four hours, which gave me chance to catch up on some light reading. We were lucky in that the shaft had broken right next to some road works, so I had company. We had almost finished putting the wheel back together again when the lady on the traffic control told us that buffalo were on their way and they were now dangerously close and to shelter behind her truck. They get quite spiky when they come near humans and need to see a clear path past. They are huge at close quarters, and whiff a bit.

Fort Nelson and Fort St John were plain sailing. Days got shorter, nights longer and the temperature slowly rose. From Fort St John we were in new territory heading for Dawson’s Creek where the Alcan highway starts. It was only here that we felt we had returned back to normal. It was so much warmer; fields of wheat interspersed with forests and deciduous woodland and gently rolling hills led us all the way to Jasper, Lake Louise and Banff. Day one in Jasper was red hot, then the temperature dropped dramatically and rain spoilt our time in this beautiful area. We moved on via the Icefield Parkway to Lake Louise where the weather failed to improve. This is a stunning part of Canada, but without good weather you cannot fully appreciate the magnificent scenery. We didn’t want to break camp and put the tent up again in rain so we did a day trip south to Banff, another great place.

The day we left Lake Louise the sun came out so we headed for the lake, along with half of Japan. It is the most visited place in Canada and we can see why. We have always thought that Lake Wakatipu in New Zealand was the best lake in the world until we saw Lago General Carrerra in Chile, but now Lake Louise is right up there tying equal first with these other two watery icons. Digital cameras were worn out that morning, but photographs cannot capture the essence of the place. The only downside to the lake is the eyesore of a huge hotel, right by the lakeside and doubtless fabulously expensive to stay in. We carried on south through the Kootenay Rockies, the location of the 2010 Winter Olympics, and on into Montana in the USA via Glacier National Park, another stunning location, south towards Great Falls and through the Little Belt mountains, into Wyoming and into Yellowstone national park via Mammoth Hot Springs.

Immediately south of Yellowstone lies Grand Teton National Park and this place we rave about. Lake Jackson is now another lake to add to the list of must-sees. Alaska and the Yukon are cold since they lie so far north, British Colombia, Montana and Wyoming are freezing cold at night in a tent due to the high altitude, usually around 6000 to 7000 feet above sea level. We dumped our plans to camp further south and camped on the shore of Lake Jackson. It was a glorious, hot day. The water was so cold it hurt just to dip our feet in it. I do not like swimming in cold water. Maybe the altitude had gotten to my brain, but for some reason I put on my cozzie and walked in up to my vitals. My legs ached with cold, but I went all the way. Below a certain temperature, it’s like anesthetic. Brain does not communicate with skin. Bob followed. I have now been told that if I can get in that, I have no excuse whatsoever for baulking at getting into any mass of water, sea or lake. Damn. I didn’t think of that. This whole area is a skiing mecca, focusing around Jackson town. Shopping opportunities are legion. In such circumstances Bob adopts his anti-retail therapy strategy of walking at breakneck pace down the centre of the road. It’s what has kept him so fit all these years.

Our mileage increased to over 31,000 into Colorado, through Steamboat Springs, over Rabbit Ear pass and on into Littleton just out of Denver. This was journeys end, where we are now staying with Bill and Jeanne Bollondonk, good friends with a variety of MGs. The two blokes are busy working on the rear axle as I write and there is more work in other areas to do yet. On the last few miles I nearly had a Thelma and Louise moment, you know, "let’s just keep driving" but common sense prevailed.

I have to mention another theme running through our journey through the USA and Canada – bears. I have long had a fixation about bears since watching Yogi bear, Booboo and Mr Ranger Sir in Jellystone park on the kids cartoons of the 1960’s. I so wanted to see a grizzly in the wild. We have seen numerous black bears, adults and youngsters, a young grizzly in Yosemite at amazingly close quarters, and plenty of bear footprints. We have camped in bear country where we have used bear-proof food boxes provided by park rangers, stayed on a campsite surrounded by an electrified fence to keep out a large colony of black and grizzly bears. We have stayed on a commercial campsite where a big adult grizzly was forming a habit of visiting late at night. We’ve watched TV news of bears launching themselves through kitchen windows to get at food. We are satiated with bears, but we still haven’t seen that quintessential sight of a grizzly catching wild salmon. That’s for another time.