Sorcha - I believe you may be confusing the Santa Ana winds with the complex weather trend El Niño. I linked to the Santa Anas further up. U have experience with both. here in los Anegeles an El Niño condition results in anything BUT dry winds. The last time we had one it caused severe flodding, mudslides and very cold weather. Of course, in the Midwest, the effect of an El Niño condition is diffeerent - it causes drought conditions. The article linked to below explains it all. In summary, Hot Dry winds in southern Cali = Santa Anas.

See here:

El Niño ( what it really is)