Typhoon Haiyan, seen here in a NEXSAT satellite image, packed sustained winds of 190 mph as it headed towards the Philippines.
Rescue workers in the Philippines are still taking stock of the devastation caused by Typhoon Haiyan.
The category 5 cyclone wreaked havoc on coastal communities, and as many as 10,000 people may have been killed.
Haiyan is being described as a "super storm."
It started like all typhoons when upper and lower sections of the atmosphere begin moving in opposite directions.
NASA climate scientist Bill Patzert says this atmospheric instability is fed by warm air coming off the ocean. September, October and November are typically the warmest months for the ocean, he said.
"And in the western Pacific where this formed, that's where we find the warmest surface temperatures in the ocean," Patzert said.
But Haiyan had another factor helping it grow: location. It formed in wide open ocean water, far from the influence of land, which Patzert says usually dampens a storm's intensity.
"So when this happens, you get a very, very intense typhoon. What they call 'super typhoons,' " he said.
Patzert says there's not enough data to say whether or not climate change had a role in this particular storm since typhoons of this size are not unheard of in the region.
But he says climate change will likely make extreme weather more common and that means more potential trouble for coastal communities across the globe.