Hurricane Francine came ashore in southern Louisiana on Wednesday, pounding New Orleans with heavy rains and gusty winds while threatening the wider Gulf Coast with a potentially deadly storm surge that led to evacuation orders for thousands of people.

While tropical storms and categories 1 and 2 are not to be taken lightly, it's when we reach Category 3 that a storm reaches "major hurricane" status and has a greater increase for loss of life and property damage. Here is a breakdown of the storm categories, as explained by the National Hurricane Center.

Tropical Depression Francine made landfall in Louisiana Wednesday as a Category 2 hurricane before being downgraded back to a tropical storm.

Francine made landfall just after 5 p.m. local time. The storm’s maximum sustained winds hovered about 100 mph and brought the potential for power outages.

Warm ocean water is essential for forming and strengthening hurricanes. Heat helps the water evaporate faster, fueling the storm and producing more rainfall. Mid-September is typically the peak of hurricane season and Francine moved through a part of the ocean that held an exceptional amount of energy.

The storm could drive life-threatening coastal flooding, high winds, drenching rain and a few tornadoes, forecasters said.

Hurricane Francine has intensified into a category 2 hurricane, with the eye nearing the Louisiana coast, the U.S. National Hurricane Center said on Wednesday. "Life-threatening storm surge and hurricane conditions spreading onto the Louisiana coast,