Related Clues:

• Grows more intense
• Strengthens
• Dredges
• Intensifies
• Becomes more profound
• Excavates further
• Falls more
• Digs down further
• Gets more interesting, say
• Gets more profound
• Increases in intensity, as a storm
• Make further down, say ditch
• Increases in intensity
• Extends farther down
• Gets more complicated