By Alastair Leithead
BBC News, Kabul
The small digital display next to the clock on the car dashboard read -4C (24.8F). But then it was 0600 in Kabul, in January.
As the sun slowly started to pour light into the city we headed north out of the bustle of the slushy streets, across the Shomali plain near the big American air base at Bagram, and up towards the snow-capped peaks of the Hindu Kush.
Officials believe 200 people have died in the recent cold weather
And as the sun gradually turned the white mountain tops shades of red, the thermometer drifted ever downwards -6C, -7C, -8C, before settling on a nice even -11C.
It was one of those beautifully clear days with a piercing blue sky.
We passed icing-sugar coated walnut trees, stone houses clinging to the mountain sides, and women clad in burkhas the colour of the sky, climbing upwards, making steep tracks in the snow until they disappeared from sight.
The tops of some vehicles - caught when the blizzards came - could still be seen poking out of the drifts beside the road, as could the triangular signs informing anyone who could make them out, or who cared, that there were dangerous bends in the road ahead.
Local people say the winter has been the most severe in decades
But Afghans do not let two metre (6ft) snow drifts and a slight chill in the air stop them driving at ridiculous speeds. That is once they have defrosted their diesel.
I would not have thought lighting a fire under the fuel tank was the best way of getting the engine running, but it is a very popular method on the road to Mazar-e-Sharif.
We had put snow chains on the back wheels of our 4x4 and made good progress through the ice and snow.
I was a little surprised when amid a beeping of horns and a cloud of powder snow, a coach, packed with people and topped with luggage, skidded past us at a crossroads.
The Salang Tunnel was built by Russia in the 1960s
"To be honest the Panshiris are mad," my colleague Mahfouz said in a matter-of-fact sort of way.
Here, Mazar-e-Sharif is to the left, the Panshir valley to the right: once the heartland of the mujahideen fighters whom the Russians never managed to tame.
We approached the Salang Tunnel, the gateway to the north. And as a spindrift of snow - like a snake of steam - wriggled left and right across the frozen road ahead of us, the car plunged into the mouth of the tunnel and into an otherworldly smog of darkness and fumes.
The odd broken-down truck emerged from the haze just in time for us to slide past it, and then we emerged out again into the pin-sharp morning as -9C glowed from the dashboard.
The journey was taking us into one of the few Afghan provinces where farmers have been persuaded to stop growing opium poppies.
An impressive achievement, mainly down to the relative security, law and order, and the strength and determination of the local governor.
Since the fall of the Taleban, the opium trade has boomed
He showed me a glossy guidebook on how he had managed to get rid of the opium poppies.
The front cover shows him dressed in a shalwar kameez, smashing down poppies with a stick. Quite a contrast to the Italian-suited politician with handmade Gucci shoes standing in front of me.
He laughed off the suggestion that he himself was involved with the opium smuggling gangs who hide drugs in their trucks and take them to Iran and Central Asia.
But the men we met the next morning told us a different story about corrupt officials.
Dodging donkeys and camels heading to market, laden with kindling, we drove first to one house then another.
Smuggling drugs, it seems, is even bigger business here than growing them
We spent time sipping tea and huddled around metal-drummed "buchari" heaters constantly fed with firewood.
Finally, we reached a mud compound in a village where the bearded drug dealers were quite happy to show us the opium they had got from elsewhere and the cannabis which has filled the financial gap left by the absence of local poppies.
Smuggling drugs, it seems, is even bigger business here than growing them.
Back in Mazar-e-Sharif I wandered round a place that is largely at peace past the famous twin-domed shrine, and walked through the crazy mobile phone market, stopped for tea, ate rice and kebabs.
Then the phone rang.
A friend in Kabul was in the five-star Serena Hotel, formerly a haven of peace and security in the capital. But a bomb had just gone off, and there was shooting all around her.
Eight people died and more were injured. It was the first attack specifically targeting international aid workers and civilians in Afghanistan.
I rushed back to Kabul the next day to report on the story.
What a different landscape it was, emerging from the otherworldliness of the Salang tunnel and down into a changed city. An ever more paranoid place where Westerners are killed for being Western, and the many beautiful things about this country are forgotten.
From Our Own Correspondent was broadcast on Saturday ,19 January, 2008 at 1130 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.