One driver suffered minor neck pains in the collisions which happened on the Exeter-bound carriageway just after 7.30am.
The trio of Newton Abbot cars were a silver Vauxhall Vivaro, a brown Skoda Yeti and a grey VW Golf.
Other vehicles were a red Vauxhall from Torquay, a white Citroen from Birmingham and a silver BMW 318 registered to an owner in North Yorkshire.
The road was reported to be clear by 9am.
The crashes were the lull before Storm Jake which produced a rapid run of hailstorms and heavy showers across south Devon from 10am.
Trees were reported down on the A380 - this time with a fir tree across the Exeter-bound carriageway at Ideford - and in Kingsteignton Road at Chudleigh.
There were also accounts of a tree down near the newly-opened South Devon Link Road between Penn Inn and Edginswell.
Firefighters from Newton Abbot dealt with a tree which fell against a property at Venn Farm, near Denbury.
In Ashburton, work premises at Linhay Business Park were briefly without power just after 10am when lightning struck.
Misha McMahon, of the Big Peaks bike and watersports store, said: ‘The power went off for about a minute-and-a-half. No damage was done.’