1) Arrest 2) Backup 3) Backup at the lumber mill 4) Big backup 5) Blockage 6) Bottleneck 7) Check 8) Congestion 9) Halt 10) Hitch 11) Immovable blockage 12) Immovable pileup 13) Impasse 14) Impediment to river traffic 15) Legislative holdup 16) Lumber mill blockage 17) Lumbering problem 18) Massive impasse 
A group of horizontal logs pushed together by wind or water flow to form an obstruction. In lakes, logjams are usually found close to shore and in the backs of coves.
[n] - any stoppage attributable to unusual activity 2. [n] - an immovable mass of logs blocking a river
noun an immovable mass of logs blocking a river
an immovable pileup or tangle of logs, as in a river, causing a blockage. · any blockage or massive accumulation: a logjam of bills before Congress.