original: Atlantic hurricane seasons Pre-1600 1600s / 10s 1620s / 30s Observation data for years before 1492 is completely unavailable because record keeping was virtually non-existent in the pre-Columbian era, and any records that may have once existed have long since been lost.
simplifications: Data before 1492 is not available, keeping records basically did not exist in the pre-Columbian era. Any records that did exist have been lost. Observation data for Hurricanes for years before 1492 is completely unavailable because record keeping was almost non-existent and lost. Observation data before 1492 isn't available because record keeping didn't exist in the pre-Columbian era. Any records that may have existed are lost. Hurricane observation data for years before 1492 is completely unavailable. Record keeping was non-existent in the pre-Columbian era. Any records have long since been lost. Atlantic hurricane seasons: Pre-1600 1600s / 10s 1620s / 30s: Observation data for years before 1492 is not available because record keeping was virtually non-existent in the pre-Columbian era. Any records that may have existed have long since been lost. There is no observation data for years before 1492 because record keeping was not in the pre-Columbian era. Any records have long since been lost. Pre-1600, 1600s ,10s,  1620s,  30s Atlantic hurricane Observation data for years before 1492 is unavailable because record keeping was virtually non-existent in the pre-Columbian era, and any records that may have once existed have long since been lost. There is almost no data about hurricanes before 1492 because there was very little recordkeeping then and any records that may have existed have been lost. Observation data for Atlantic hurricane seasons in years before 1492 is completely unavailable because record keeping was almost non-existent in the pre-Columbian era. Any records that did exist have been lost. Atlantic hurricane seasons Pre-1600s/10s 1620s/30s Analysis data for years prior to 1492 is completely unavailable because record keeping was virtually non-existent in the pre-Columbian era, and any records that may have existed have been lost for a long time.