Hurricanes end when they lose their source of energy, often by traveling over land or over cold water. Hurricanes require a steady supply of warm, moist air to fuel the rotation that keeps the storm moving, and when that source is cut off, the cyclone quickly uses up what energy it has and dissipates.
Hurricanes form over the open ocean, when warm air full of moisture rises from warm waters. This creates a low pressure area near the surface, and surrounding air rushes in to fill the void. This constant movement sets up the trademark rotation of a tropical storm, allowing it to build stronger winds and denser clouds. The longer a hurricane travels over warm waters being fed by moisture and warm air, the stronger it becomes.
As soon as a hurricane makes landfall, it can no longer rely on a warm updraft and moisture from the water below to power its engine. The stored energy inside a hurricane can power it for some time, allowing these storms to travel far inland and do damage. However, as soon as the hurricane runs out of its saved fuel, it begins to slow down and end.
Once a hurricane has traveled inland, it is highly unlikely it will gain strength again, as the atmospheric conditions over land won't provide it with the fuel it needs to grow. Once a hurricane moves over land, it encounters more friction than it did when moving over water, which further slows its progress. In some cases, a hurricane's demise can be hastened by powerful wind shear, strong winds in opposing directions that disrupt the storm's rotation and cause it to fail quickly.