MONTERREY, Mexico (AP) _ People using picks or their bare hands dug through rubble where their homes had stood, and the search wore on for the bodies of people who died when a river overran its banks and swept away four buses.

As of Sunday, rescue workers had found the bodies of 90 of the nearly 200 people believed killed the previous day when a flash flood spawned by Hurricane Gilbert caused the normally dry Santa Catarina River to overflow.

The torrent ripped a 40-mile path of destruction through northern Mexico's most populated region, on which Gilbert had dumped about 12 inches of rain in 24 hours after leaving the Gulf of Mexico.

Gilbert, which killed at least 194 people during its week of life, was today a tropical depression that was spreading showers and thunderstorms from Texas to Illinois.

In Mexico, 31 died when the storm slammed into Mexico's Yucatan peninsula Wednesday with winds of up to 200 mph. One woman drowned in floodwaters Sunday in the coastal state of Tamaulipas.

The storm killed 30 people in Haiti, 26 in Jamaica, five in the Dominican Republic and eight in Honduras in its deadly rampage through the Caribbean. Two people were killed in Texas by tornados spawned by the storm and a pilot died in Oklahoma when his plane broke apart in heavy rains.

President Miguel de la Madrid, surveying the destruction in this northern industrial city on Sunday, said Mexico has ''a lot to lament.''

Parts of two major thoroughfares and hundreds of homes built by the poor in the dry Santa Catarina riverbed were swept away by the raging waters.

Although homes had been evacuated hours before the destruction hit, most residents lost their life's possessions. Officials said about 30,000 in the region were homeless.

Many residents used picks or bare hands to dig through the rubble that remained where their tiny concrete and tin houses had stood.

Rescue workers continued to search for bodies, and Jose Natividad Gonzalez Paras, Nuevo Leon state secretary, said a ''considerable number'' of people still were missing.

Journalists saw soldiers uncover the body of one man caught in the mangled remains of an electricity tower.

The man, who appeared about 20 years old, had been covered by clothing, tree branches and mud trapped by the tower, one of several downed lines along the Santa Catarina's bank at the hardest-hit area.

Further downstream, two dozen soldiers used cranes to pull the crushed and overturned body of an intercity passenger bus from the mud and sand of the riverbed.

''They hope to find bodies because they don't know exactly how many people were in the bus or how many were able to save themselves,'' said rescue coordinator Lt. Col. Vicente Gamez of the 7th Military Zone.

The first bus yanked from the riverbed and hauled away revealed only empty seats, twisted metal and piles of shoes and clothing. The three other buses remained buried upside down Sunday night.

Gamez said rescue crews were searching for bodies in Cadereyta, about 20 miles downstream, where the flood wiped out homes and killed more than a dozen people.

Hundreds of families farther downstream were evacuated to public buildings on higher ground Sunday because of flooding, said Fernando Gonzalez Villarreal, assistant secretary in the federal Water Resources Ministry.

''The situation is critical. The rain was very strong,'' he said.

Nuevo Leon state authorities estimated damages to public roads, bridges and other facilities alone at $60 million.

Thirteen U.S. Coast Guard airplanes and helicopters flew rescue missions on Sunday throughout Nuevo Leon and Tamaulipas states, assisting Mexican air forces.

A Coast Guard helicopter being used for evacuation lost power as it took off on Sunday and fell about 50 feet, brushing a house under construction, police reported.

''The chopper made a forced landing. Fortunately, no one was hurt,'' said Lt. Commander John Wcislo, U.S. Coast Guard attache in Mexico.

Police said the three Americans and one Mexican on board were taken to the local hospital for a checkup and released.

Wcislo said Coast Guard aircraft would continue ferrying people and Red Cross supplies today if needed.