A method for forming a secure attachment to a roof of a building, the method comprising: positioning a first roof-anchoring device at or near a first edge of the roof such that a first axle of the first roof-anchoring device is located under and in a first tensioned contact with the first edge while a second axle of the roof-anchoring device is on the roof and a first connector pivotally attached to the second axle is under tension due to a first force pulling said first connector away from the second axle up the roof, wherein said first roof-anchoring device includes a first arched body having first and second ends, the first axle juxtaposed with the first arched body at the first end, the second axle juxtaposed with the first arched body at the second end, and said first connector; disposing a second roof-anchoring device near a second edge of the roof such that a third axle of the second roof-anchoring device is located under and in a second tensioned contact with the second edge while a fourth axle of the second roof-anchoring device is in contact with and on the roof and a second connector pivotally attached to the fourth axle is under tension due to a second force pulling said second connector away from the fourth axle up the roof, wherein said second roof-anchoring device includes a second arched body having third and fourth ends, the third axle juxtaposed with the second arched body at the third end, the fourth axle is juxtaposed with the second arched body at the fourth end, and said second connector; wherein said first and second connectors are linked with a tether line under strain configured to maintain the first and second tensioned contacts while preventing said first and third axles from moving away from first and second edges of the roof. positioning a first roof-anchoring device at or near a first edge of the roof such that a first axle of the first roof-anchoring device is located under and in a first tensioned contact with the first edge while a second axle of the roof-anchoring device is on the roof and a first connector pivotally attached to the second axle is under tension due to a first force pulling said first connector away from the second axle up the roof, wherein said first roof-anchoring device includes a first arched body having first and second ends, the first axle juxtaposed with the first arched body at the first end, the second axle juxtaposed with the first arched body at the second end, and said first connector; disposing a second roof-anchoring device near a second edge of the roof such that a third axle of the second roof-anchoring device is located under and in a second tensioned contact with the second edge while a fourth axle of the second roof-anchoring device is in contact with and on the roof and a second connector pivotally attached to the fourth axle is under tension due to a second force pulling said second connector away from the fourth axle up the roof, wherein said second roof-anchoring device includes a second arched body having third and fourth ends, the third axle juxtaposed with the second arched body at the third end, the fourth axle is juxtaposed with the second arched body at the fourth end, and said second connector; wherein said first and second connectors are linked with a tether line under strain configured to maintain the first and second tensioned contacts while preventing said first and third axles from moving away from first and second edges of the roof.