an irrigation sprinkler including a base defining an axis , a pressurized water inlet mounted onto the base , a nozzle , communicating with the inlet , and providing a pressurized water stream which is generally outwardly directed relative to the axis and a water stream deflector for engaging the pressurized water stream and deflecting at least part of the water stream azimuthally with respect to the axis , the deflector including a first pressurized water stream engagement surface and a second pressurized water stream engagement surface downstream of the first engagement surface , the first engagement surface having a pressurized water stream directing configuration arranged to direct a first portion of the stream impinging thereon , which does not exceed a predetermined quantity , onto the second surface and to direct at least a second portion of the stream impinging thereon , which at least a second portion exceeds the predetermined quantity , not onto the second engagement surface .