وَكَرَامَتُهُ ظُهُورُ أَمْرٍ خَارِقٍ لِلْعَادَةِ مِنْ قِبَلِهِ
His karāmah is the appearance of an event outside ordinary custom.
ʿĀdah refers to the customary observed order of events. A departure from it is not necessarily a logical contradiction. Allah's power is not confined to the familiar sequence of ordinary causes.
But recognizing that an event would be unusual, establishing that it happened, and classifying it as karāmah are separate steps.