with border patrol chief who was showing us the points where they cross. we had more than four groups crossing in just one hour. as the groups were crossing the chief talked about the dangers the migrants face at this part of the journey. listen to this. >> you can see that we're having to pick their steps. the footing is precarious. gravel bottoms, some silt in some areas. if they slip and fall, you know, we run the risk of someone drowning and -- >> harris, that rock bottom you can see is just pebbles, very slippery. yesterday a 74-year-old grandmother from venezuela making this cross all those migrants in the footage yesterday were from venezuela. it is very difficult for her and dangerous for her. in some parts there are the currents that you see. i'll leave you with this one