godan verb (-ru), intransitive verb
become bright with sunlight after a shower
Describes the moment when the sun comes out and the surroundings brighten after rain. Often used in literary or descriptive contexts.
にわか雨がやんで、あたりが急に照り上がった。
The shower stopped and the area suddenly became bright with sunlight.
照る is a general verb for the sun shining, while 照り上がる specifically describes the brightening effect after rain.
Compound of 照り (continuative form of 照る, 'to shine') and 上がる ('to rise, go up'), literally 'to shine up'. The exact historical derivation is uncertain, but the meaning is transparent from its components.