The 1911 Sonora hurricane was a deadly tropical cyclone that had effects that extended far inland, producing significant flooding in the U.S. state of Colorado.

After crossing the peninsula and the Gulf of California, the hurricane moved ashore the Mexican state of Sonora with strong winds and high tides.

It moved northwestward, eventually making landfall along the western Baja California peninsula on October 4, just west of La Paz.

The hurricane's remnant low moved across the southwestern United States through Arizona, near the Four Corners region, and into Colorado, where it dropped heavy rainfall.

[1]: 25 [2][3] Before the hurricane made landfall, it produced high waves that lashed the steamer Nevadan on October 3, while it was sailing 50 mi (80 km) north of Cabo San Lucas.

[4] At San José del Cabo, the hurricane destroyed the sugar cane crop from its strong winds.

In the same city, floodwaters surpassed the seawall and inundated coastal areas 3 ft (0.91 m) deep, causing heavy damage.

[7] The hurricane left Guaymas and the nearby mining town of Rosalia short on water and food supply.

[10] Following a summer of above normal precipitation, the remnants of the hurricane moved across the southwestern United States, producing a widespread area of rainfall that first affected Arizona and Utah.

The heaviest rainfall occurred in Colorado, reaching 8.16 in (207 mm) at Gladstone in the San Juan Mountains at an elevation of 10,400 ft (3,200 m).

[1] After a summer of above-normal rainfall, the floods in early October occurred over such a widespread area that the United States Weather Bureau assessed there being "no previous record, or even tradition, among the Indians of such severe floods occurring simultaneously in all the streams of southwestern Colorado and northwestern New Mexico."

The town of Arboles, located 35 mi (56 km) downstream, experienced the floods about five hours later, with the river swelling 17 ft (5.2 m) above normal.

At Del Norte, officials warned sleeping residents with a fire bell, before floodwaters covered the town up to 3 ft (0.91 m) deep.