With this convective activity gradually consolidating, the system organized into a tropical depression by 12:00 UTC on October 17[c] about 400 nautical miles southwest of Manzanillo, Mexico.

Situated within an environment of warm sea-surface temperatures (SSTs), low vertical wind shear, and plentiful moisture, Norma underwent an almost two-day long period of rapid intensification shortly after forming, as a ridge over Mexico steered the system to the north while gradually slowing it down.

Norma reached its peak intensity as a Category 4 hurricane at 12:00 UTC on October 19, with maximum sustained winds of 210 km/h (130 mph) and a minimum barometric pressure of 939 mbar (27.7 inHg).

[1] After peaking in intensity, increased dry air and wind shear caused Norma's structure to degrade, and the storm weakened slightly as it turned northwestward and began to move more quickly.

Despite this, increasingly cooler SSTs caused the hurricane to weaken rapidly as it turned north between the ridge over Mexico and a trough to its northwest.

Norma made landfall on the Mexican state of Baja California Sur near 20:15 UTC on October 21 as a Category 1 hurricane, with maximum winds of 130 km/h (80 mph).

Strong upper-level winds produced by the trough caused Norma's convective activity to be sheared away, and the storm weakened to a depression as it moved inland over the state of Sinaloa at 10:30 UTC on October 23.

[1] Tropical storm and hurricane warnings were issued in advance of Norma’s landfalls, with the NHC anticipating rainfall totals of up to 460 mm (18 in) across portions of northwestern Mexico.

[6][8] The port of La Paz was closed, leaving over 400 people stranded onboard a ferry crossing the Gulf of California from Sinaloa.

The governor also stated that he was not anticipating financial assistance from the Mexican federal government to cover the cost of damage produced by Norma.

Schools remained closed in parts of the state into Monday as clean-up crews removed fallen trees and scattered debri across La Paz.

[21] Norma dumped heavy rainfall and caused widespread power outages across southern areas of Sinaloa as it made landfall on the state as a tropical depression.

Broken glass, fallen trees and damage to homes and business was reported, mainly in the municipalities of Los Mochis, Ahome and Guasave.