Lewis Hamilton set the pace in the dry in Friday's second practice for the Canadian GP only to crash his W06 on his very first lap in the wet.
With rain forecast – expected after the opening half an hour of the session – the drivers were quickly out onto the Circuit Gilles Villeneuve.
Ferrari were straight onto the supersoft tyres with Sebastian Vettel clocking a 1:16.304 to go quickest ahead of team-mate Kimi Raikkonen. Just 0.006s separated the Ferrari drivers.
Mercedes soon followed suit, trying to get in some supersoft running. Hamilton initially struggled to get in a clean lap as despite being purple in the first two sectors, he lost it at the final chicane and hit the kerbs hard.
But when the Brit did get it right he went quickest with a 1:15.988 and was leading by 0.316s when the rain began to fall with 53 minutes remaining.
Although no rain is forecast for the rest of the weekend, it wasn't long before the Mercedes pairing ventured out. That proved to be a mistake for Hamilton as he aquaplaned off the track and into the barrier at the hairpin, damaging the front end of his W06.
Adding insult to injury, when the crane lifted Hamilton's car, pulling it out of the tyre wall, it swung and hit the recovery vehicle. There did not appear to be any additional damage.
The session was red flagged as the rain continued to fall but was green lighted again with 28 minutes remaining. However with the rain getting steadily heavier there were no takers and FP2 ground to a quiet and wet conclusion.
That meant Hamilton's weekend began with back-to-back P1s while Vettel was second ahead of Raikkonen and Nico Rosberg.
Pastor Maldonado was fifth quickest for Lotus ahead of Valtteri Bottas and Romain Grosjean. The trio were the last drivers to get within a second of Hamilton's P1 time.
1 Lewis Hamilton Mercedes 1:15.988 22 laps
2 Sebastian Vettel Ferrari 1:16.304 0.316 19 laps
3 Kimi Raikkonen Ferrari 1:16.310 0.322 20 laps
4 Nico Rosberg Mercedes 1:16.440 0.452 22 laps
5 Pastor Maldonado Lotus 1:16.600 0.612 15 laps
6 Valtteri Bottas Williams 1:16.849 0.861 18 laps
7 Romain Grosjean Lotus 1:16.864 0.876 15 laps
8 Felipe Massa Williams 1:17.041 1.053 19 laps
9 Daniil Kvyat Red Bull 1:17.092 1.104 10 laps
10 Daniel Ricciardo Red Bull 1:17.111 1.123 16 laps
11 Nico Hulkenberg Force India 1:17.120 1.132 16 laps
12 Marcus Ericsson Sauber 1:17.261 1.273 17 laps
13 Carlos Sainz Toro Rosso 1:17.318 1.330 23 laps
14 Sergio Perez Force India 1:17.367 1.379 20 laps
15 Fernando Alonso McLaren 1:17.627 1.639 21 laps
16 Max Verstappen Toro Rosso 1:17.657 1.669 23 laps
17 Felipe Nasr Sauber 1:17.751 1.763 21 laps
18 Jenson Button McLaren 1:18.135 2.147 20 laps
19 Roberto Merhi Manor 1:19.531 3.543 15 laps
20 Will Stevens Manor 1:19.734 3.746 13 laps