Very low tides on Monday 21 March 2011

Especially low levels of low water were reached on the Channel and Atlantic coasts at low tide on Monday 21 March 2011. The extreme equinoctial tides with a coefficient of 118 were combined with the anticyclone conditions established over France. The high pressures developed a reduction in height that caused the level of the astronomic tide to fall.

Meteorogical situation on 21/03/2011 at 12h

Table of tide gauges that were working and measured the most noteworthy low tides on 21 March:

Port	Height of low tide observed	Height of low tide predicted	Reduction in low tide value	Atmospheric pressure observed	Level of lowest astronomical low tide	Estimated statistical return period for the low tide observed	The 3 lowest low tides measured
Le Conquet	0,07 m (le 21/03/2011 à 11h30 UT)	0,34 m	-0,27 m	1033 hPa	0,25 m	50 ans	20/03/2007 à 10h50 UT 0,14 m (coeff 115) 01/03/2006 à 11h30 UT 0,24 m (coeff 114) 20/02/1992 à 20h00 UT 0,08 m (coeff 113)
Roscoff	0,11 m (le 21/03/2011 à 12h30 UT)	0,31 m	-0,20 m	1034 hPa	0,17 m	entre 20 et 50 ans	20/03/2007 à 12h20 UT 0,07 m (coeff 115) 10/03/1997 à 12h30 UT 0,09 m (coeff 118) 19/02/1988 à 12h50 UT 0,13 m (coeff 114)
Cherbourg	0,22 m (le 21/03/2011 à 14h40 UT)	0,39 m	-0,17 m	1034 hPa	0,29 m	entre 10 et 20 ans	20/03/2007 à 15h30 UT 0,28 m (coeff 115) 10/03/1997 à 15h40 UT 0,13 m (coeff 118) 20/02/1996 à 15h50 UT 0,07 m (coeff 113)

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