As Hortense approached Puerto Rico, the eastern half of the circulation had a concentrated area of thunderstorms. While the hurricane crossed the southwest portion of the island, it dropped heavy rainfall of over in much of the territory's eastern half. Totals ranged from below near where the storm moved ashore to a peak of near Cayey. Three stations broke their 12–hour rainfall records and two stations broke their 24–hour rainfall records; the highest 24–hour total was in Las Piedras. The rainfall caused widespread flash flooding and increased river discharge; a station along the Río Grande de Loíza in San Lorenzo reported a 1 in 100 year flow rate. Rivers and creeks across the region reached high peaks, and there were several reports of mudslides. Sustained winds on the island peaked at in Ceiba, and gusts reached in Carolina. An unofficial wind gust of in the southwest portion of the island may have been caused by the Venturi effect, or an acceleration of winds between walls. Along the southern Puerto Rico coast, Hortense caused coastal flooding and beach erosion.