Methane gas has been leaking from a storage facility in California’s Aliso Canyon since October 2015 at a rate of 110,000 pounds per hour. You can see the plume in this infrared video shot on December 17, 2015. So far, 1,700 homes have been evacuated. The Southern California Gas Company thinks it will be able to stop the leak "by late February or late March."
From Motherboard:
Part of the problem in stopping the leak lies in the base of the well, which sits 8,000 feet underground. Pumping fluids down into the well, usually the normal recourse, just isn’t working, said Silva. Workers have been "unable to establish a stable enough column of fluid to keep the force of gas coming up from the reservoir." The company is now constructing a relief well that will connect to the leaking well, and hopefully provide a way to reduce pressure so the leak can be plugged.