Unfortunately for the landing force, the planners at Pearl Harbor had completely misjudged the situation that would face Gen. Schmidt’s Marines. The beaches had been described as “excellent” and the thrust inland was expected to be “easy.” In reality, after crossing the beach, the Marines were faced with 15-foot-high slopes of soft black volcanic ash. This ash allowed for neither a secure footing nor the construction of foxholes to protect the Marines from hostile fire. However, the ash did help to absorb some of the fragments from Japanese artillery.
The Japanese kept up a desultory mortar-and-rifle fire as the Americans gradually crowded more and more men and equipment onto the beach. The lack of a vigorous response led the Navy to conclude that their bombardment had suppressed the Japanese defenses. Gen. Kuribayashi was far from beaten, however. After allowing the Americans to pile up men and machinery on the beach for just over an hour, he unleashed the undiminished force of his countermeasures. Shortly after 1000 hours, everything from machine guns and mortars to heavy artillery began to rain down on the crowded beaches.
At first it came as a ragged rattle of machine-gun bullets, growing gradually lower and fiercer until at last all the pent-up fury of a hundred hurricanes seemed to be breaking upon the heads of the Americans. Shells screeched and crashed, every hummock spat automatic fire and the very soft soil underfoot erupted underfoot with hundreds of exploding land mines … Marines walking erect crumpled and fell. Concussion lifted them and slammed them down, or tore them apart…
Time-Life correspondent Robert Sherrod described it simply as “a nightmare in hell.”
The Japanese heavy artillery in Mount Suribachi opened their reinforced steel doors to fire, and then closed them immediately to prevent counterfire from the Marines and naval gunners. This made it difficult for American units to destroy a Japanese artillery piece. To make matters worse for the Americans, the bunkers were connected to the elaborate tunnel system so that bunkers that were cleared with flamethrowers and grenades were reoccupied shortly afterwards by Japanese troops moving through the tunnels. This tactic caused many casualties among the Marines, as they walked past the reoccupied bunkers without expecting to suddenly take fresh fire from them.
In response to the heavy resistance on the beach, the Army’s 147th Infantry Regiment was ordered to climb from landing craft with grappling hooks to scale a high ridge about 3/4 mile from Mount Suribachi. The mission was to fire on the enemy opposing the Marine landings on the beaches below. They were soon pinned down by heavy Japanese fire, and engaged in non-stop fighting for 31 days before they could be relieved.