In my opinion this is not the result of a fork, but a difficulty adjustment stall.
At block 245000, the developer changed the difficulty retarget method. Before 245000, the code appeared to adjust the difficulty every 120 blocks, based on the block solving time of those 120 blocks. The Difficulty would adjust by a maximum of 4x (four times). After 245000, in an effort to reduce the strip mining effects by the multipools, the retarget scheme changed to adjust every block based on the block solving time of the previous 120 blocks with a maximum adjustment of 4x. This turned out to be a disaster with the most recent hash rate increase on the coin, because in the space of 10 blocks, the difficulty increased by a factor of over 1 million. Using the old method (pre 245000), the difficulty would have only increased by a factor of 4.
Block Difficulty
246943 0.00024414
246944 0.0004377
246945 0.0017508
246946 0.007
246947 0.028
246948 0.112
246949 0.448
246950 1.792
246951 7.171
246952 28.685
246953 114.742
246954 249.59 Not solved
If you were going to do a diff recalc every block, you wouldn't want to average over the last 120blocks, more like 4 or 5 blocks would be enough.
Now you have a real problem, it will probably need a new client release to fix as the next diff change will be higher not lower. Better get onto it quickly before exchanges and pools get mad. The changes will probably have to kick in on the next block, or the client will have to start at a lower diff somehow.