What was so abnormal about Israel's coming to Deborah?

Judges 4:5 (ESV)

5 She used to sit under the palm of Deborah between Ramah and Bethel in the hill country of Ephraim, and the people of Israel came up to her for judgment.

The normal way for Israel to learn God's judgment was for its leader to go to the high priest who had the Urim and Thummim (Exodus 28:30). The fact that the high priest was not consulted indicates that in the decadent time of the judges the priesthood did not func­tion as God had intended. In response to this sad state of af­fairs, God mercifully raised a prophetess, Deborah…. People could thus still inquire of God by going to Deborah to seek a decision or judgment from God. And they did. They were grievously suffering under the cruel oppression of Sisera.1