The Tijuana River mouth closed last week in response to what we think are the combined effects of large waves throughout this El Niño season and potentially along-shore transport of sand from earlier beach nourishments. Our colleagues at the Tijuana National Estuarine Research Reserve have been monitoring the situation closely to better understand what is going on. See this news article about some of the unfortunate consequences of this closure combined with significant water quality issues from upstream. A paper by colleagues in the Guza lab should be coming out soon that looks at the beach component of this issue. While several of the smaller estuaries throughout California close more regularly, a closure of this estuary has not occurred since the last major El Niño in 1983.