as nuance, both are like similar meaning though they are used differently. 강렬하다 is used when you describe about image things and emotional things. For example; The first impression with Tom was 강렬했다. the other 격렬하다 is likely to be used in physical stuff. For example; they fought 격렬하게/ We hugged 격렬하게. I hope you can understand what I explain. keep up learning Korean!

as nuance, both are like similar meaning though they are used differently. 강렬하다 is used when you describe about image things and emotional things. For example; The first impression with Tom was 강렬했다. the other 격렬하다 is likely to be used in physical stuff. For example; they fought 격렬하게/ We hugged 격렬하게. I hope you can understand what I explain. keep up learning Korean!