If you are in an area with frost heaves, it is possible that the bulbs may have been pushed up, especially if they were planted at shallower depths. If the area had any heavy rain, erosion may have taken away some of the soil on top, or the bulbs sitting in muddy water might rise to the surface. Also, were there any signs of digging? Animals such as squirrels may sometimes dig up bulbs. Tulips may form offsets in spring—if these bulbs look tinier than normal, it could be that these detached from the mother bulb due to heavy rain, frost heaving, etc. and rose to the surface. Hope this helps!
If you are in an area with frost heaves, it is possible that the bulbs may have been pushed up, especially if they were planted at shallower depths. If the area had any heavy rain, erosion may have taken away some of the soil on top, or the bulbs sitting in muddy water might rise to the surface. Also, were there any signs of digging? Animals such as squirrels may sometimes dig up bulbs. Tulips may form offsets in spring—if these bulbs look tinier than normal, it could be that these detached from the mother bulb due to heavy rain, frost heaving, etc. and rose to the surface. Hope this helps!