Regional Jet 900 (CRJ900)
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 150
Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
We experienced the wake turbulence encounter on the descent through FL300; initial uncommanded roll 15 to 20 deg left followed by 25 to 30 deg to the right; rolled out and escaped from the encounter. We asked Center what type of aircraft we were flying behind. The reply was a Boeing 757; which we had on screen TCAS at about 10 miles ahead of us. However there was another aircraft farther ahead of the 757 that we could also see on screen. The Center Controller allowed us to take a heading off course to remain clear of the threat. However we ran into the wake again in the vicinity of GLAVN; and was not as much of a problem during that encounter. and I thought it was strange I have never had a 757 wake encounter roll the aircraft like that. Shortly after we were on approach control into Atlanta airport we discovered that the 757 was what appeared to be slightly less than 10 miles in trail of a heavy B787.I find it unusual to be in that type of upset due to 757 wake turbulence. We followed them all the time. I think it could be possible that the 757 was so close to the preceding aircraft that the heavy aircraft's wake was not a problem for the 757; but became one for us. Given the current conditions the winds were pushing the wake in our direction [so] obviously more spacing would've helped. I don't mind a vector off course. I would greatly appreciate more spacing behind heavier aircraft.
Reporter stated he was surprised at the intensity of the wake from the preceding B757.
CRJ-900 Captain reported encountering wake turbulence on descent into ATL in trail of a B757; which was  following of a Heavy B787.