The　increase　in　power　outages　caused　by　high-impact　low-probability　events,　such　as　extreme　weather-related　climate　variation　events,　is　the　main　reason　behind　studying　power　system　resilience.　However,　the　concepts　of　resilience　as　well　as　the　proactive　procedures　that　can　be　carried　out　to　address　these　events　are　such　have　not　so　far　been　satisfactorily　investigated　notwithstanding　their　growing　benefits.　This　paper　exhibits　a　review　of　the　current　research　on　power　system　resilience;　which　predominantly　focuses　on　proactive　resilience　against　natural　disasters.　Firstly,　it　gives　a　theoretical　framework　to　acquire　insights　into　power　system　resilience　and　its　key　features.　Secondly,　it　presents　frameworks　for　proactive　resilience　of　power　systems　with　a　spotlight　on　the　extreme　weather　events　and　their　effect.　Finally,　various　strategies　for　preparing,　hardening　and　enhancing　proactive　resilience　with　a　focus　on　microgrids　for　improving　power　system　resilience　are　reviewed.