Josh Bennett-Keer (4-26) and Jonathan Lee (3-18) helped restrict Crossbank to 94-9 in their 27-over per side contest. Only Anees Rawat (31) offered much resistance.
Northowram eased to victory in 16 overs with Chris Metcalf hitting 62.
Second-placed Great Preston lost ground after a crushing nine-wicket defeat against Buttershaw St Paul’s.
An unbeaten 61 from Richard Jennings enabled East Ardsley to overhaul Heckmondwike and Carlinghow’s 124 to record a six-wicket win.
Heckmondwike were restricted by accurate bowling from David Battye (3-16) and Ashley Pearson (3-19). Adam Holt (32) top scored for Heckmondwike whose best bowler was Paul Cooper (3-27).
Joseph Finnigan claimed 6-32 as fourth-placed Wakefield St Michael’s dismissed Adwalton for 130 to secure a 136-run win after they declared on 266-9 which saw Ayaz Seedat make 88.
Gildersome proved too good for bottom team Rodley as they recorded a four-wicket win.
Arshad Jan took 4-38 as Rodley were bowled out for 92. Haseeb Hashmi then hit 34 to help Gildersome home.
East Leeds followed up their first win of the season over Crossbank by defeating Azaad.