Andrea Iannone set the pace in the opening practice session for the German MotoGP, minutes before the rain – and Jorge Lorenzo – came down.
On a cold morning at the Sachsenring Ducati's Iannone set the early benchmark time, a 1:23.702, before the rain arrived.
That put him 0.414s up on championship leader Marc Marquez while Danilo Petrucci was third, a further 0.041s off the pace.
Valentino Rossi was fourth fastest with a 1:24.279.
However, a trio of crashers as the downpour strengthened, all at the fast right-hander Turn 11, forced the riders back into the pits.
Scott Redding was the first man down in the gravel, followed by Lorenzo and then Stefan Bradl.
Lorenzo, who trails Marquez by 24 points in the riders' standings, was taken to the medical centre for checks on his left wrist where it was confirmed that there is no fracture.
The rain meant none of the riders were able to improve their times, leaving Iannone safely in the P1 slot.
Loris Baz returned to the track after spending the past few weeks recovering from the right foot fractures he sustained at Mugello. He was slowest of all down in 21st place.
1 Andrea IANNONE Ducati Team 1'23.702
2 Marc MARQUEZ Repsol Honda Team 1'24.116 0.414
3 Danilo PETRUCCI OCTO Pramac Yakhnich 1'24.157 0.455
4 Valentino ROSSI Movistar Yamaha MotoGP 1'24.279 0.577
5 Andrea DOVIZIOSO Ducati Team 1'24.352 0.650
6 Pol ESPARGARO Monster Yamaha Tech 3 1'24.487 0.785
7 Maverick VIÑALES Team SUZUKI ECSTAR 1'24.592 0.890
8 Cal CRUTCHLOW LCR Honda 1'25.141 1.439
9 Aleix ESPARGARO Team SUZUKI ECSTAR 1'25.224 1.522
10 Yonny HERNANDEZ Pull & Bear Aspar Ducati Team 1'25.282 1.580
11 Dani PEDROSA Repsol Honda Team 1'25.313 1.611
12 Jorge LORENZO Movistar Yamaha MotoGP 1'25.35 1.651
13 Hector BARBERA Avintia Racing 1'25.384 1.682
14 Alvaro BAUTISTA Aprilia Racing Team Gresini 1'25.388 1.686
15 Stefan BRADL Aprilia Racing Team Gresini 1'25.418 1.716
16 Jack MILLER Estrella Galicia 0,0 Marc VDS 1'26.369 2.667
17 Bradley SMITH Monster Yamaha Tech 3 1'26.623 2.921
18 Eugene LAVERTY Pull & Bear Aspar Ducati Team 1'26.822 3.120
19 Tito RABAT Estrella Galicia 0,0 Marc VDS 1'27.168 3.466
20 Scott REDDING OCTO Pramac Yakhnich 1'27.521 3.819
21 Loris BAZ Avintia Racing 1'29.786 6.084