WASHINGTON (AP) - The La Nina climate phenomenon is strengthening, increasing the likelihood an active hurricane season could get even busier.

The update from the National Oceanic and Atmospheric Administration on Thursday comes as residents of Texas are cleaning up from the deluge of Tropical Storm Hermine (hur-MEEN), and Tropical Storm Igor is drifting in the Atlantic.

La Nina (La NEEN-ya) is marked by a cooling of the tropical Pacific Ocean and was reported to be developing a month ago. Weather forecasters say it strengthened throughout August and appears likely to last at least through early 2011.