0km - No change at the top, with Nibali leading Evans by 1:26 and Uran by 2:46.
0km - Top ten today: 1. Visconti, 2. Betancur +42, 3. Niemiec +42, 4. Majka +42, 5. Duarte +47, 6. Scarponi +54, 7. Nibali +54, 8. Evans +54, 9. Santambrogio +54, 10. Uran +54.
0km - The race favourites come home 49 seconds down so there will be little if no change at the top tonight.
0km - Another second place for Carlos Betancur, who crosses the line 41 seconds down ahead of Niemiec and Majka.
0km - Victory for Giovanni Visconti (Movistar). There's hardly a smile on his face as he punches the air - the Italian is clearly exhausted.
0.2km - A Lampre rider has joined Betancur, Duarte and Majka - perhaps Niemiec.
0.3km - Visconti will hold on for an astonishing victory.
0.5km - Betancur caught by Duarte and Majka.
0.7km - Duarte attacks and Rabottini tries to hold his wheel. And now Betancur goes!
1km - Visconti passes under the 1km-to-go banner. he has a minute and should hold on.
1.2km - Majka attacks! Betancur follows! So does Nibali - and eventually Evans and Scarponi and the others.
1.3km - Uran, Scarponi and Evans are all there in the pink jersey group. Santambrogio too.
1.5km - Rabottini is about to be caught by Kelderman, but the small group of favourites will soon sweep them both up.
1.7km - The main pack sweeps up Sanchez and Caruso - and Nibali attacks with Kangert!
2km - We forgot about Wilco Kelderman: the Blanco youngster has now caught and passed Weening and rides solo in pursuit of Rabottini. Duarte has caught Sanchez, Weening and Caruso.
2.5km - It's looking very good for Visconti, who continues to extend his lead over Rabottini on this final climb. Sanchez and Caruso have caught and passed the blue jersey, Pirazzi, while Michele Scarponi edges clear of the Astana-led peloton.
3km - The snow starts to fall now as we enter the final few kilometres of the stage.
3.5km - Now Astana come to the front of the pack: Nibali has three men, including Estonia national champion Tanel Kangert, setting the pace. And there's an attack from one of the Colombia riders: Fabio Duarte.
4km - Rabottini is riding with one earpiece of his radio hanging loose. He's 1:05 down on Visconti now, with the Sanchez-Caruso duo 2:10 down and the peloton at 2:22.
5km - Samuel Sanchez of Euskaltel jumps clear of the pack. He's taken a Cannondale rider with him. It's Damiano Caruso. Petrov of Saxo Bank tries to stay with him, but can't keep the pace.
5.5km - Visconti has never won a stage in the Giro before so this would be the crowning moment of the 30-year-old's career. He has 55 seconds over Rabottini, who has won a stage in the Giro before (last year's stage 15) but who is struggling to cut the deficit. The pack rides at 2:30 without any massive movement so far.
6km - Surely Evans and Uran will have to make their moves soon if they want to put Nibali under some pressure? The gap to Visconti is 2:25 so it's touch and go for the Italian. But Rabottini is making no in-roads: he's still 53 down on the leader.
7km - Now the rain starts to fall onto Visconti, who still holds 44 seconds over Rabottini and 2:30 over the pack.
7.5km - Garate and Petrov are back in the pack. So just four riders out ahead: thge leader, Visconti, the chaser, Rabottini, then the Weening-Pirazzi duo. Make that five: Wilco Kelderman of Blanco has now attacked from the peloton.
8km - This is a wonderful ride from Visconti, who is above all a sprinter over a climber. He leads Rabottini by 38 seconds with Weening and Pirazzi abother 10 seconds back. The Gesink-Henao group has been swept up by the pack, and another Blanco rider - Juan Manuel Garate - has pulled out with Evgeni Petrov of Saxo Bank. They have just 10 seconds over the pack.
9km - Cadel Evans still has BMC team-mate Steve Moribito with him. The Majka move was neutralised and the main pack is now quite large. The weather is still ok but live images from the top indicate rain and slushy snow falling.
10km - The Gesink group pass under the 10-to-go banner 2:15 down on Visconti.
10.5km - Now Rabottini attacks: the Italian puts in another dig and this time he has distanced both Pirazzi and Weening. The Vini Fantini man trails the lone leader by 44 seconds.
11km - Now Saxo-Tinkoff have come to the front of the main pack - and Rafal Majka has been paced off the front by Evgeni Petrov. Colombian Carlos Betancur smells a trick and closes it down - he's only trailing the white jersey Majka by seven seconds in the youth standings.
12km - Rabottini, the stage 15 winner from last year's Giro, puts in a big dig but Weening and Pirazzi manage to reel him in.
12.5km - Visconti has 54 seconds over the Pirazzi group and 2:15 over the Gesink group. The peloton rides another 30 seconds down.
13km - Lone leader Giovanni Visconti is onto the Col du Galibier. Because of the snow, we're not going all the way to the top - but instead the stage will finish 4km from the summit at the Marco Pantani memorial monument. The average gradient is 5.8% with a maximum gradient of 11%.
14km - Visconti is approaching the end of this small summit and he will now pass through Valloire and then start the final climb of the Col du Galibier.
16km - Pirazzi just managed to hold on to second place over the summit. Confirmation of result over the Telegraph: 1. Visconti 9pts, 2. Pirazzi 5pts, 3. Weening 3pts, 4. Rabottini 2pts, 5. Chalapud 1pt. Pirazzi extends his lead to 67 points to Chalapud's 29.
17km - The peloton cross over the summit 2:56 down with Gastauer just ahead.
18km - The Gesink group is still 1:55 down on Visconti, the lone leader, who crosses the summit of the Telegraph in pole position. Pirazzi looks set to take the points for second place 45 seconds down, but Weening seems to just pip him to it. Rabottini is foruth.
20km - Gesink, his jersey open and his face a picture of concentration, clearly wants to get his Giro back on track with a win today. The Dutchman is the one driving the pace - and Henao, Rubiano, Chalapud and even Di Luca are struggling to stay in touch.
21km - The Henao/Gesink group trails the lone leader Visconti by 1:42. Herrada rides at 2:13 and the main pack at 2:40. Weening, Rabottini and Pirazzi are a bit down on Visconti still.
22km - Movistar's Jose Herrada attacked from the peloton and has caught Betancur in pursuit of the chasing group. In fact, it's not Betancur but Baston Gastauer. Betancur is still in the main pack.
23km - Visconti has jumped clear of the other three leaders and holds a 10-second gap over Weening, Pirazzi and Rabottini. The Gesink/Henao/Martinez/Kiserlovski group has been joined by Di Luca and are riding at 1:30. They pass Bongiorno and leave him for dead - although the youngster appears to give Di Luca a high-five as he passes.
23.5km - The maglia rosa looks very serene as he rides in the wake of four Astana team-mates with Cadel Evans, his main rival, stuck to his back wheel - like a piece of chewing gum to a boot, or like a piece of bog roll caught on the Italian's Versace shoes after a trip to the gabinetto.
24km - It's Betancur - and he's taken Vini Fantini's Danilo Di Luca with him. Meanwhile, further up the road Henao and Kiserlovski have joined Martinez and Gesink.
24.5km - Attack from one fo the Ag2R-La Mondiale riders from the main pack. We're on helicopter images so it's hard to see whether it's Betancur or Pozzovivo.
25km - The main pack is now only about 30-strong. Visconti and Rabottini have joined Pirazzi and Weening on the front. Meanwhile, Martinez has urged Gesink to slow the tempo a bit as the pair continue their pursuit of the leaders.
26km - Now Sergio Henao of Sky has attacked from the main pack. The Sky man slipped to 13th on GC yesterday and has gone up the road to pave the way for his Colombian compatriot and team-mate Rigoberto Uran. Henao has joined De Greef and Robert Kiserlovski of RadioShack.
26.5km - It's now just blue jersey Pirazzi and Weening out ahead. Visconti and Rabottini have joined forces in the chase, while further down the hill, Gesink and Euskaltel's Martinez are riding at 1:37. The peloton is 2:10 down.
27km - Francis De Greef cannot keep up with Egoi Martinez and Robert Gesink. Back on the front, Bongiorno has cracked and Chalapud is being distanced too. Weening leads the break, with Pirazzi, Rabottini and Visconti all behind.
27.5km - Gesink is joined by De Greef and Martinez. Danielson was there but he has faded. Back with the leaders and Rubiano has cracked.
28km - ATTACK: Robert Gesink of Blanco pulls clear of the main pack. He'll be keen to make a splash after conceding so much time yesterday.
28.5km - Bongiorno paces his Bardiani Valvole team-mate Stefano Pirazzi on this first segment of the climb, with Visconti in his wheel. Pirazzi won't be able to hold on to win this stage, but he could still take the 9pts available at the top of the Telegraph, and that would further cement his lead in the blue jersey.
29km - Lotto are leading the main pack as they start the climb as Cadel Evans sheds his arm warmers. The Italian is right on the wheel of pink jersey Vincenzo Nibali.
30km - The leaders are onto the Cat.2 Col du Telegraph, a 12km climb with an average gradient of 7.2km and a maximum gradient of 11%.
31km - The lead is now down to 2:15 as the break approaches the climb.
32km - Lotto Belisol are still bossing the front of the peloton - for no apparent reason. There's one Ag2R-La Mondiale rider just ahead of them, mind. The French team have Domenico Pozzovivo and Carlos Betancur as cards to play today. The Colombian has come very close to winning a stage this year, with two seconds and, yesterday, one third.
35km - The advantage of this break is coming down quite rapidly: it's just 3:20 now and you have to fear for these seven riders.
40km - Three Lotto Belisol riders have come to the front of the main pack - perhaps trying to set things up for their man Francis de Greef? Back with the leaders, one of the two Colombians, Robinson Chalapud, has a problem with his radio and unplugs before handing it over to his team car. He'll be completing the rest of the stage 'au naturel'.
43km - We still have about 15km of gentle downhill ahead of the Col du Telegraph.
45km - Rabottini and Chalapud shed both their leg and arm warmers ahead of the final back-to-back climbs. Meanwhile, off the front of the peloton pedal two Lotto Belisol riders, who are being closely monitored by Astana.
48km - Six minutes now the gap for the leaders ahead of the business end of the stage. Visconti has pulled out on the descent but he'll be joined by his six companions soon. The Italian was the first blue jersey of the race and wore it for six stages, with a one-day loan of the jersey to Willem Wauters of Vacansoleil for stage four.
51km - Rubiano picks up maximum points at the intermediate sprint at Aussois ahead of Visconti and Rabottini. Now the leaders will freewheel to the foot of the Col du Telegraph.
57km - Reminder of the seven leaders: Stefano Pirazzi and Francesco Bongiorno (both Bardiani Valvole), Robinson Chalapud (Colombia), Pieter Weening (Orica-GreenEdge), Giovanni Visconti (Movistar), Matteo Rabottini (Vini Fantini) and Miguel Angel Rubiano (Androni Giocattoli). The gap is 5:28.
60km - With Weening caught, the seven leaders have five minutes over the main pack now. Many riders are discarding their layering up once again - but there no snow now they're back in the valley. Astana are setting the pace in the peloton. Most of their riders are in fully blue attire - but Nibali has black leg warmers and not the team regulation blue ones.
63km - Weening is onto the slight rise ahead of the intermediate sprint at Aussois. He still has 20 seconds over the six chasing riders. Of all the escapees, he's the best placed on GC. But his 47-minute deficit to Vincenzo Nibali means Astana are not too interested in chasing this one down, hence the four-minute gap that has now established.
67km - Pirazzi, Bongiorno, Chalapud and Androni Giocattoli's Miguel Angel Rubiano catch Visconti and Rabottini to form one chase group in pursuit of Weening, who is currently stuffing his face with chocolate, cereal bars and energy gels. The Dutchman has 24 seconds, with the peloton 3:10 back.
70km - Pieter Weening, 32, won a stage in the 2011 Giro d'Italia while riding at Rabobank. He joined GreenEdge in 2012 but is still looking for his first win with the Australian outfit. He is being pursed by Gio Visconti, who has dropped the other escapees in pursuit of the lone leader. Actually, the Movistar rider has not been joined by Rabottini, who won a stage during last year's Giro. They trail Weening by 22 seconds.
75km - Weening has 30 seconds over the five chasers and a further two minutes over the peloton, which is being led by the baby blue jerseys of Astana, the team of race leader Vincenzo Nibali.
80km - Dutchman Pieter Weening (Orica-GreenEdge) has pulled out ahead of the other escapees and leads the race heading down the hill. Weening was involved in the break yesterday before crashing out with two others just moments after the group formed.
82km - A leading group formed going over the summit and they have decided to press on - so that's it for the neutralised section. We have six riders in the break: Stefano Pirazzi and Francesco Bongiorno (both Bardiani Valvole), Robinson Chalapud (Colombia), Pieter Weening (Orica-GreenEdge), Giovanni Visconti (Movistar) and Matteo Rabottini (Vini Fantini).
85km - That was an ideal scenario for Stefano Pirazzi, who was followed over the line by a Bardiani Valvole team-mate - Francesco Bongiorno - to deny Robinson Chalapud the points for second place. The Italian is now on 62 points with the Colombian second in the KOM standings on 28.
86km - The peloton cross over the summit 1:38 down on Pirazzi. There's a feed zone right over the top and many riders stop to put on more layers and take their musettes.
88km - Pirazzi rides clear to take the points at the top and consolidate his lead in the blue jersey competition.
89km - There are around half a dozen riders chasing down the two leaders, who are playing a tactical game of cat and mouse.
90km - ATTACK: Finally some action as Stefano Pirazzi, the blue jersey, breaks clear of the trundling bunch in pursuit of those mountain points. No surprises who follows him: that man Robinson Chalapud.
91km - Everyone is preparing themselves for the descent with arm warmers, snoods, windbreakers etc. It's freezing up there - although some riders have eschweed the leg warmers and opted for regular bib shorts, including hard man Patrick Gretsch of Argos Shimano.
92km - Every now and then the roads are covered with a thin layer of running water that has come from the melting banks of snow that line the roads. Some of these water traps may well be freezing and slippery - and presumably that is the fear for the descent on the other side of the summit.
94km - The riders are passing the Lac Mont Cenis, formed after the construction of a dam. There is quite a lot of snow on the side of the road, but the actual road is clear and the sun is out at the moment. The temperature is cold though, with riders in gilets and jackets and leg warmers. Rigoberto Uran has just put on a whooly hat underneath his helmet, plus a pair of gloves.
95km - Contrary to the earlier comment, the border with France is in fact just coming up right now. This slow pace means the riders are significantly behind the expected scheduling.
96km - The enforced slow pace continues. There's a neutral motorbike filled with bidons riding on the front and giving some of the front runners a chance to take fresh bottles. It remains to be seen what happens at the top of the summit regarding the KOM points.
98km - Forner race leader Luca Paolini, winner of stage four, has ridden ahead of the pack to chat to compatriot Paolo Bettini, one of the race officials. Not sure what's going on at the moment, but the riders seem to be showing some kind of solidarity together by agreeing to tackle this climb as one unit before, no doubt, renewing hostilities for the remainder of the stage.
100km - The temperature at the top of Mont Cenis is zero degrees Celsius. The group is still riding as one as some kind of enforced go-slow has been instated. As far as we're aware, there are KOM points available at the top and so at some point during this long climb we can surely expect some kind of movement.
101km - David Walsh, the journalist who has rallied against bringing Lance Armstrong to justice for most of the past 14 years, has made his thoughts clear about today's 'Pantani stage': "Professional sport played its part in Pantani's death; UCI, sponsors, officials, TV, journalists, fans all contributed. The monument is an attempt, deliberate or otherwise, to deny our guilt and his cheating. What about monument to those who were cheated!"
102km - There is a suggestion that the slow pace has in fact come about after discussions with the race organisers - that the start of the stage has effectively been neutralised as first had been planned. More on that when we ge it.
103km - The average speed for the first hour today was 37.8kmh, which was pretty slow considering most of that was downhill.
104km - Now the Astana team of maglia rosa Vincenzo Nibali have come to the front of main pack, their pace causing the first riders to be tailed off the back. But it's short lived as the pace suddenly slows, allowing everything to come back together.
106km - The pace is very slow today, with a suggestion from the Italian journalist Davide Cassani than the peloton is riding slowly intentionally to avoid a high disqualification time for those who will struggle later today. Rai TV also report that Vini Fantini directeur sportif Luca Scinto will shave his head should his team take a second consecutive win today in the Alps...
108km - Coming up is the hamlet of Giaglione after which the race crosses the border into France. This climb connects the Val di Susa with the French region of Haute Maurienne in the department of Savoie.
110km - The riders are onto the first climb of the day, the Cat.1 Col du Mont Cenis (25km long at an average of 6%).
115km - It will be unlikely for any break to form until the start of the Mont Cenis climb, which starts in about 5km once the peloton passes through Susa.
120km - It's very much a two horse race in the battle for the white jersey, with Carlos Betancur - third yesterday - now just seven seconds behind Poland's Rafal Majka (Saxo-Tinkoff). The Colombian from Ag2R-La Mondiale has finished second twice and third once now - he's been consistently brilliant. Third in the standings is Dutchman Wilco Kelderman (Blanco) who is almost eight minutes down.
125km - Bert De Backer (Argos Shimano) has a pop at breaking away on the downhill but he's given short shrift by the peloton. Belgian De Backer was the only rider of a five-man break a few days ago not to come to grief on a slippery bend during the monsoon that was stage 12 to Treviso. He clearly has confidence when the road heads down...
130km - Winner of four stages this year, Mark Cavendish leads the red jersey competition with 109 points to Cadel Evans's 83. Cav needed to did deep to complete yesterday's stage within the time limit - and he finished 22:31 down on the winner Santambrogio, surrounded by five loyal Omega Pharma-Quick Step team-mates. Last to fionish on the stage was Australian Nathan Haas of Garmin-Sharp, who brought up the rear a huge 25:24 down. Chapeau!
135km - The remaining 180 riders are making their way downhill towards the town of Susa on this 32km drag down to the valley ahead of the first climb of the day. No attacks to report so far.
140km - As mentioned earlier, today's finish will be at the Marco Pantani memorial monument, which marks the spot where feted Italian rider attacked in the rain to secure victory in the 1998 Tour de France. Although a controversial figure in the sport, Pantani's name and memory is still a huge motivating factor for many current riders - so expect attacks galore on the final climb.
145km - Stage 15 of the Giro d'Italia is under way - and expect a fierce battle from the GC rivals ahead of the second rest day.
12:00 - After yesterday's mist and rain, the weather is much more clement today. The sun is peeking through the clouds and there are patches of blue in the sky - although there's still a fair bit of snow alongside the road on the climbs of Mont Cenis and Col du Galibier. Indeed, so much snow on the latter that the road is blocked to the summit.
11:55 - With or without the Col du Mont-Cenis, we can expect a fierce battle for KOM points today. Italian Stefano Pirazzi (Bardiani Valvole) leads the standings on 47 points with Venezuelan Jackson Rodriguez (Androni Giocattoli) in second on 26. Colombia's Robinson Chalapud is third on 23 points while yesterday's winner Mauro Santambrogio (Vini Fantini) moves into fourth on 18.
11:50 - After finishing second yesterday and ahead of his rivals, Vincenzo Nibali extended his lead at the top of the general classification. The Italian from Astana is now 1:26 ahead of Australian veteran Cadel Evans (BMC) with Colombian Rigoberto Uran (Team Sky) in third at 2:46. Mauro Santambrogio (Vini Fantini) is up to fourth at 2:47 with Michele Scarponi (Lampre) fifth at 3:53. After shipping more than four minutes yesterday, Dutchman Robert Gesink (Blanco) drops out of the top ten.
11:45 - The 145km stage will start with a fast 32km downhill towards the foot of the Cat.1 Col du Mont Cenis - which may or may be neutralised depending on the weather. The descent is punctuated by a slight ride and plateau ahead of the first intermediate sprint at Aussois and then the downhill run to the foot of the Cat.2 Col du Telegraph. Then there's a short downhill to Valloire before the final climb up the Cat.1 Col du Galibier to the Pantani monument 4.25km from the summit.
11:40 - Today's stage was due to start at 11:35 UK time but the alterations to the parcours have led to a slight delay and the riders will now leave the start at Cesana Torinese at midday.
11:35 - Yesterday, Vincenzo Nibali tightened his grip on the pink jersey with a second-place finish atop the Jafferau climb behind fellow Italian Mauro Santambrogio in a weather-affected stage 14. The Italian duo emerged through the mist shoulder-to-shoulder with 500m remaining of the altered 180km stage in the Alps. Astana's Nibali was content to allow Santambrogio of Vini Fantini take a maiden win on the Giro d'Italia - and his wildcard team's first of the 96th edition of the race.
11:30 - Despite fears that the Col du Galibier and Mont Cenis would be cut from today's stage due to snow and poor weather, the race organisers have come to an agreement with local officials in France and the race will go ahead with the finish just 4km shy of the summit, alongside the Marco Pantani memorial monument. The stage is now 145km long and it will be decided today whether or not the first climb of Mont Cenis is neutralised.
11:25 - Welcome to LIVE coverage of stage 15 of the Giro d'Italia - a gruelling Alpine slog that finishes not quite atop the fabled Col du Galibier.