At 2136 eastern standard time (EST) on January 31, 2011, 0236 coordinated universal time (UTC) February 1, 2011, a runway excursion and runway incursion involving a single airplane occurred at the James M. Cox Dayton International Airport (DAY), Dayton, Ohio. The airplane involved was ExpressJet (BTA) 2693, an Embraer E145 that had departed from Cleveland Hopkins International Airport (CLE), Cleveland, Ohio with 3 crew and 29 passengers on a scheduled part 121 flight to DAY. There were no injuries to the passengers or crew. The airplane sustained damage to the left main gear door, auxiliary gear door and the number 2 main tire. The reported weather at 2056 EST was wind 070 at 12 knots, visibility 10 statute miles, overcast ceiling at 1,900 feet above ground level (AGL). Temperature minus 5 degrees Celsius, dew point minus 10 degrees Celsius, altimeter 30.11 inches of mercury. A special observation taken after the incident at 2139 reported wind 070 at 8 knots, visibility 7 statute miles in light freezing rain, overcast ceiling at 1,900 feet AGL, temperature minus 4 degrees Celsius, dew point minus 8 degrees Celsius, altimeter 30.10 inches of mercury, freezing rain began at 2133 and snow began falling at 2119 ending at 2133 with a total accumulation of .01 inches of snow. Automatic Terminal Information Service (ATIS) information alpha was being broadcast at the time of the incident. ATIS A reported "0155Z, wind 060 at 11, visibility 10, ceiling 1,900 overcast, temperature -5, dew point -10, altimeter 3011, landing and departing runway 6L, 6R, 36. ILS approach 6L in use. Notice to airmen taxiway W closed. Hazardous weather information available. Read-back hold-short instructions." There were no braking action advisories in effect. While descending en-route to DAY, BTA2693 encountered intermediate light rime icing. There was no mention of precipitation on the DAY ATIS. According to the pilot's statement, he suspected freezing rain at the airport due to temperature changes during the descent. BTA2693 was vectored by Dayton approach control for an ILS approach to 6L before being transferred to the DAY air traffic control tower (ATCT). DAY closed runway 6L for anti ice treatment. BTA2693 elected to fly the ILS runway 6L approach, circle to land runway 6R. After reporting the airport in sight, the DAY local controller (LC) cleared BTA2693 to land on runway 6R. After issuing a landing clearance to BTA2693, the DAY local controller solicited a braking action report from an aircraft that had previously landed; Labquest 650A. Labquest 650A advised that he did not brake on landing but the "taxiways and ramps were slick." During this period of time while BTA2693 was still on the approach on the DAY local control frequency, field maintenance advised ATC on the local control frequency that there was ice present on runway 6L and a possibility of ice on runway 6R. This information was relayed by the DAY local controller to BTA2693 prior to landing. BTA2693 acknowledged with "we'll let you know". According to the airplane captain, the first officer (FO) was flying the airplane on the final approach with the precipitation alternating between ice and rain. As the airplane reduced speed for approach and landing, the icing developed from moderate mixed to moderate clear icing. The FO turned on his windscreen wipers which blurred his view of the field. The captain's view was clear so he took over as the flying pilot and continued flying for the remainder of the approach and landing. The initial roll out was without incident. As the airplane decelerated through 80 to 60 knots the captain noticed a small amount of sliding slightly to the right. The captain said he corrected the aircraft to maintain centerline at which time the aircraft began to slide significantly to left. The captain said he used full thrust reversers to slow the airplane with negligible effect. The airplane continued toward the left side of the runway. The captain said he applied and maintained light brake pressure, full right rudder, and differential thrust reverser (full right), but could not correct the leftward motion of the aircraft. As the aircraft continued toward the left side of the runway, the captain said he "retracted the left thrust reverser, added positive thrust on the left engine and full reverse on the right engine trying to steer the airplane to the right like a boat." When it was apparent that the airplane's path could not be altered and that the airplane was going to depart the runway, the captain re-applied the left thrust reverser and added maximum reverse on both engines. BTA2693 departed the left side of runway 6R several hundred feet from the intersection of Runway 6R and runway 36, coming to a stop on runway 36 facing northeast. BTA2693 departed runway 6R resulting in a runway excursion. BTA2693 came to a stop on runway 36, an active runway resulting in a runway incursion. There were no other aircraft using runway 36 at the time and there was no risk of ground collision. The pilots stated that they did not notice any type of lurching or loud sounds that could have been associated with airplane damage and that there was no sense that the landing gear were sinking into the ground. The pilots also stated that the grassy area in the vicinity of the intersection of runway 6R and 36 was frozen tundra with 6-12 inches of snow and ice. Post incident photographs taken by Atlantic Southeast Airways on the evening of the incident captured the tire tracks in the grassy area where BTA2693 exited the left side of the runway 6R, a damaged distance remaining marker and the base stand of the distance remaining marker. The photographs show very little accumulation of snow and ice. An exterior inspection of the airplane by airport operations personnel and a test of the airplane steering and rolling system by the pilots indicated no apparent damage preventing the airplane from taxiing. After airport operations sanded the taxiway, BTA2693 taxied under its own power to the gate. The DAY local controller advised BTA2693 of possible ice on runway 6R prior to landing however weather observation at the time of approach and landing did not include precipitation. After landing BTA2693 reported to the tower that they had nil braking action and were off the runway. When BTA2693 reported that they were off the runway to the DAY local controller, the transmission was made at the same time as an airfield vehicle was making a report to the same controller. The simultaneous transmissions conflicted with each other. BTA2693 advised that they were at the intersection of runway 6R and runway 18 and that they required an inspection prior to taxiing to the gate. The DAY local controller was not aware that BTA2693 had departed runway 6L. Since the DAY local controller said he was not aware of a runway excursion, no notification of an incident was reported to the FAA until February 10, 2011.