When pressures and temperatures become unbalanced in the atmosphere of the Earth, it can produce some dramatic effects as the system tries to rebalance itself, or re-equilibrate (i.e. reach equilibrium). Many of these changes are things that, on a small scale, we are used to witnessing every day in the form of weather, such as wind, rain, snow, fog, etc.
Sometimes, however, very large imbalances can cause massive and very disruptive change. The extreme weather events of 2011 are good examples of extreme changes in pressure and temperature that required re-balancing (equilibration). Not only did they have environmental impacts, but also disastrous consequences for the hundreds and thousands of people in their wake.