Regional Jet 900 (CRJ900)
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Physiological - Other; Workload; Distraction
Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Weather / Turbulence
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Weather
While descending along the I believe around 18;000 ft. we hit a pretty strong first bump. Followed by smooth air and then another very large violent bump. Again followed by smooth air I believe the altitude was around 16;500 ft. and then we encountered severe turbulence. I originally had the flight spoilers out to help the descent to make the crossing altitude and speed at the first altitude speed fix. The turbulence was the worst I have ever experienced which the Captain had also said was the worst. The airspeed began increasing to the point we were going to overspeed so I powered back and decreased the rate of descent as I was descending in vertical speed mode. The turbulence had gotten so severe I couldn't even read the instruments displays. We then had a very large and immediate decrease in speed of 50 kts. in the matter of seconds which then forced me to go into the climb detent again. I had at some point in the craziness of the turbulence hit my head on the ceiling of the aircraft. I did have my seat belt fastened but I do not remember if I had the shoulder harnesses on as we were above 10;000 ft. My first reaction in all of this was to maintain control of the airplane not to get my shoulder harness on and possibly stall the airplane.At one point I saw an area with no clouds to the right and told the Captain to ask for an immediate right deviation. The frequency was blocked so I took authority and immediately turn 90 degrees to the right and thankfully a minute later it smoothed out between 10;000 to 12;000 ft. I did realize in the descent that I did have the flight spoilers out 2 to 3 notches due to the aircraft nearly over speeding but had forgot to stow them due to the flight situation we were encountering. I did stow them as soon as I realized they were still deployed. During the initial severe turbulence the Captain went to advise the Flight Attendants over the phone so I had the radios and was pilot flying and advised Center or approach of the situation and they came back saying there was only moderate reported before I could barely speak due to the vibrations of the severe turbulence but advised we are in severe. They had asked if anyone was hurt or if there was any aircraft damage which I told them I do not know the answer to either but I will advise when we can. We advised them when we were out of the severe that there weren't any passenger injuries and we don't believe if there was any aircraft damage but we couldn't see what was going on outside.At some point in the severe turbulence the Captain had gotten her hand or wrist slammed against something which she was in pain for crying the rest of the flight. When we both got on the ground I felt okay originally but then as the adrenaline began to wear off I began having a splitting headache and soar-ness on the top of my head. Both the Captain and I went to an urgent care on our layover. A line of weather existed along our route at the time and even though we were VMC approaching the tops we had encountered the severe turbulence.
CRJ First Officer reported encountering severe turbulence that caused injuries to the flight crew.